Last data update: Nov 04, 2024. (Total: 48056 publications since 2009)
Records 1-30 (of 37 Records) |
Query Trace: Lemons AR[original query] |
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Corrigendum: Persisting Cryptococcus yeast species Vishniacozyma victoriae and Cryptococcus neoformans elicit unique airway inflammation in mice following repeated exposure
Rush RE , Blackwood CB , Lemons AR , Dannemiller KC , Green BJ , Croston TL . Front Cell Infect Microbiol 2024 14 1381148 [This corrects the article DOI: 10.3389/fcimb.2023.1067475.]. |
Optimization of Aspergillus versicolor culture and aerosolization in a murine model of inhalational fungal exposure
Blackwood CB , Croston TL , Barnes MA , Lemons AR , Rush RE , Goldsmith T , McKinney WG , Anderson S , Weaver KL , Sulyok M , Park JH , Germolec D , Beezhold DH , Green B . J Fungi (Basel) 2023 9 (11) Aspergillus versicolor is ubiquitous in the environment and is particularly abundant in damp indoor spaces. Exposure to Aspergillus species, as well as other environmental fungi, has been linked to respiratory health outcomes, including asthma, allergy, and even local or disseminated infection. However, the pulmonary immunological mechanisms associated with repeated exposure to A. versicolor have remained relatively uncharacterized. Here, A. versicolor was cultured and desiccated on rice then placed in an acoustical generator system to achieve aerosolization. Mice were challenged with titrated doses of aerosolized conidia to examine deposition, lymphoproliferative properties, and immunotoxicological response to repeated inhalation exposures. The necessary dose to induce lymphoproliferation was identified, but not infection-like pathology. Further, it was determined that the dose was able to initiate localized immune responses. The data presented in this study demonstrate an optimized and reproducible method for delivering A. versicolor conidia to rodents via nose-only inhalation. Additionally, the feasibility of a long-term repeated exposure study was established. This experimental protocol can be used in future studies to investigate the physiological effects of repeated pulmonary exposure to fungal conidia utilizing a practical and relevant mode of delivery. In total, these data constitute an important foundation for subsequent research in the field. |
Fungal diversity in homes and asthma morbidity among school-age children in New York City
Cochran SJ , Acosta L , Divjan A , Lemons AR , Rundle AG , Miller RL , Sobek E , Green BJ , Perzanowski MS , Dannemiller KC . Environ Res 2023 239 117296 BACKGROUND: Asthma development has been inversely associated with exposure to fungal diversity. However, the influence of fungi on measures of asthma morbidity is not well understood. OBJECTIVES: This study aimed to test the hypothesis that fungal diversity is inversely associated with neighborhood asthma prevalence and identify specific fungal species associated with asthma morbidity. METHODS: Children aged 7-8 years (n = 347) living in higher (11-18%) and lower (3-9%) asthma prevalence neighborhoods were recruited within an asthma case-control study. Fungal communities were analyzed from floor dust using high-throughput DNA sequencing. A subset of asthmatic children (n = 140) was followed to age 10-11 to determine asthma persistence. RESULTS: Neighborhood asthma prevalence was inversely associated with fungal species richness (P = 0.010) and Shannon diversity (P = 0.059). Associations between neighborhood asthma prevalence and diversity indices were driven by differences in building type and presence of bedroom carpet. Among children with asthma at age 7-8 years, Shannon fungal diversity was inversely associated with frequent asthma symptoms at that age (OR 0.57, P = 0.025) and with asthma persistence to age 10-11 (OR 0.48, P = 0.043). Analyses of individual fungal species did not show significant associations with asthma outcomes when adjusted for false discovery rates. DISCUSSION: Lower fungal diversity was associated with asthma symptoms in this urban setting. Individual fungal species associated with asthma morbidity were not detected. Further research is warranted into building type, carpeting, and other environmental characteristics which influence fungal exposures in homes. |
Reduction of exposure to simulated respiratory aerosols using ventilation, physical distancing, and universal masking (preprint)
Coyle JP , Derk RC , Lindsley WG , Boots T , Blachere FM , Reynolds JS , McKinney WG , Sinsel EW , Lemons AR , Beezhold DH , Noti JD . medRxiv 2021 2021.09.16.21263702 To limit community spread of SARS-CoV-2, CDC recommends universal masking indoors, maintaining 1.8 m of physical distancing, adequate ventilation, and avoiding crowded indoor spaces. Several studies have examined the independent influence of each control strategy in mitigating transmission in isolation, yet controls are often implemented concomitantly within an indoor environment. To address the influence of physical distancing, universal masking, and ventilation on very fine respiratory droplets and aerosol particle exposure, a simulator that coughed and exhaled aerosols (the source) and a second breathing simulator (the recipient) were placed in an exposure chamber. When controlling for the other two mitigation strategies, universal masking with 3-ply cotton masks reduced exposure to 0.3–3 µm coughed and exhaled aerosol particles by > 77% compared to unmasked tests, whereas physical distancing (0.9 or 1.8 m) significantly changed exposure to cough but not exhaled aerosols. The effectiveness of ventilation depended upon the respiratory activity, i.e., coughing or breathing, as well as the duration of exposure time. Our results demonstrate that a combination of administrative and engineering controls can reduce personal inhalation exposure to potentially infectious very fine respiratory droplets and aerosol particles within an indoor environment.PRACTICAL IMPLICATIONSUniversal masking provided the most effective strategy in reducing inhalational exposure to simulated aerosols.Physical distancing provided limited reductions in exposure to small aerosol particles.Ventilation promotes air mixing in addition to aerosol removal, thus altering the exposure profile to individuals.A combination of mitigation strategies can effectively reduce exposure to potentially infectious aerosols.Competing Interest StatementThe authors have declared no competing interest.Funding StatementThis work was supported by the Centers for Disease Control and Prevention Emergency Operations Center.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Not ApplicableAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesThe datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request. |
Face mask fit modifications that improve source control performance (preprint)
Blachere FM , Lemons AR , Coyle JP , Derk RC , Lindsley WG , Beezhold DH , Woodfork K , Duling MG , Boutin B , Boots T , Harris JR , Nurkiewicz T , Noti JD . medRxiv 2021 2021.09.16.21263642 BACKGROUND During the COVID-19 pandemic, face masks are used as source control devices to reduce the expulsion of respiratory aerosols from infected people. Modifications such as mask braces, earloop straps, knotting and tucking, and double masking have been proposed to improve mask fit. However, the data on source control are limited.METHODS The effectiveness of mask fit modifications was determined by conducting fit tests on human subjects and simulator manikins and by performing simulated coughs and exhalations using a source control measurement system.RESULTS Medical masks without modification blocked ≥56% of cough aerosols and ≥42% of exhaled aerosols. Modifying fit by crossing the earloops or placing a bracket under the mask did not increase performance, while using earloop toggles, an earloop strap, and knotting and tucking the mask increased performance. The most effective modifications for improving source control performance were double masking and using a mask brace. Placing a cloth mask over a medical mask blocked ≥85% of cough aerosols and ≥91% of exhaled aerosols. Placing a brace over a medical mask blocked ≥95% of cough aerosols and ≥99% of exhaled aerosols.CONCLUSION Fit modifications can greatly improve the performance of face masks as source control devices for respiratory aerosols.Competing Interest StatementThe authors have declared no competing interest.Funding StatementResearch was supported by the following sources: Centers for Disease Control and Prevention, National Institutes of Health R01 ES015022 (TRN) and WV-CTSI U54 GM104942-05.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:WVU Protocol #: 2009119037All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesData is available from research personnel upon request. |
Persisting Cryptococcus yeastspecies Vishniacozyma victoriae and Cryptococcus neoformans elicit unique airway inflammation in mice following repeated exposure
Rush RE , Blackwood CB , Lemons AR , Green BJ , Croston TL . Front Cell Infect Microbiol 2023 13 1067475 BACKGROUND: Allergic airway disease (AAD) is a growing concern in industrialized nations and can be influenced by fungal exposures. Basidiomycota yeast species such as Cryptococcus neoformans are known to exacerbate allergic airway disease; however, recent indoor assessments have identified other Basidiomycota yeasts, including Vishniacozyma victoriae (syn. Cryptococcus victoriae), to be prevalent and potentially associated with asthma. Until now, the murine pulmonary immune response to repeated V. victoriae exposure was previously unexplored. OBJECTIVE: This study aimed to compare the immunological impact of repeated pulmonary exposure to Cryptococcus yeasts. METHODS: Mice were repeatedly exposed to an immunogenic dose of C. neoformans or V. victoriae via oropharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) and lungs were collected to examine airway remodeling, inflammation, mucous production, cellular influx, and cytokine responses at 1 day and 21 days post final exposure. The responses to C. neoformans and V. victoriae were analyzed and compared. RESULTS: Following repeated exposure, both C. neoformans and V. victoriae cells were still detectable in the lungs 21 days post final exposure. Repeated C. neoformans exposure initiated myeloid and lymphoid cellular infiltration into the lung that worsened over time, as well as an IL-4 and IL-5 response compared to PBS-exposed controls. In contrast, repeated V. victoriae exposure induced a strong CD4(+) T cell-driven lymphoid response that started to resolve by 21 days post final exposure. DISCUSSION: C. neoformans remained in the lungs and exacerbated the pulmonary immune responses as expected following repeated exposure. The persistence of V. victoriae in the lung and strong lymphoid response following repeated exposure were unexpected given its lack of reported involvement in AAD. Given the abundance in indoor environments and industrial utilization of V. victoriae, these results highlight the importance to investigate the impact of frequently detected fungal organisms on the pulmonary response following inhalational exposure. Moreover, it is important to continue to address the knowledge gap involving Basidiomycota yeasts and their impact on AAD. |
Efficacy of Do-It-Yourself air filtration units in reducing exposure to simulated respiratory aerosols
Derk RC , Coyle JP , Lindsley WG , Blachere FM , Lemons AR , Service SK , Martin SB Jr , Mead KR , Fotta SA , Reynolds JS , McKinney WG , Sinsel EW , Beezhold DH , Noti JD . Build Environ 2023 229 109920 Many respiratory diseases, including COVID-19, can be spread by aerosols expelled by infected people when they cough, talk, sing, or exhale. Exposure to these aerosols indoors can be reduced by portable air filtration units (air cleaners). Homemade or Do-It-Yourself (DIY) air filtration units are a popular alternative to commercially produced devices, but performance data is limited. Our study used a speaker-audience model to examine the efficacy of two popular types of DIY air filtration units, the Corsi-Rosenthal cube and a modified Ford air filtration unit, in reducing exposure to simulated respiratory aerosols within a mock classroom. Experiments were conducted using four breathing simulators at different locations in the room, one acting as the respiratory aerosol source and three as recipients. Optical particle spectrometers monitored simulated respiratory aerosol particles (0.3-3 μm) as they dispersed throughout the room. Using two DIY cubes (in the front and back of the room) increased the air change rate as much as 12.4 over room ventilation, depending on filter thickness and fan airflow. Using multiple linear regression, each unit increase of air change reduced exposure by 10%. Increasing the number of filters, filter thickness, and fan airflow significantly enhanced the air change rate, which resulted in exposure reductions of up to 73%. Our results show DIY air filtration units can be an effective means of reducing aerosol exposure. However, they also show performance of DIY units can vary considerably depending upon their design, construction, and positioning, and users should be mindful of these limitations. |
Spring is associated with increased total and allergenic fungal concentrations in house dust from a pediatric asthma cohort in New York City
Cochran SJ , Acosta L , Divjan A , Lemons AR , Rundle AG , Miller RL , Sobek E , Green BJ , Perzanowski MS , Dannemiller KC . Build Environ 2022 226 Introduction: Asthma and allergy symptoms vary seasonally due to exposure to environmental sources of allergen, including fungi. However, we need an improved understanding of seasonal influence on fungal exposures in the indoor environment. We hypothesized that concentrations of total fungi and allergenic species in vacuumed dust vary significantly by season. Objective: Assess seasonal variation of indoor fungi with greater implications related to seasonal asthma control. Methods: We combined next-generation sequencing with quantitative polymerase chain reaction (qPCR) to measure concentrations of fungal DNA in indoor floor dust samples (n = 298) collected from homes participating in the New York City Neighborhood Asthma and Allergy Study (NAAS). Results: Total fungal concentration in spring was significantly higher than the other three seasons (p ≤ 0.005). Mean concentrations for 78% of fungal species were elevated in the spring (26% were significantly highest in spring, p < 0.05). Concentrations of 8 allergenic fungal species were significantly (p < 0.5) higher in spring compared to at least two other seasons. Indoor relative humidity and temperature were significantly highest in spring (p < 0.05) and were associated with total fungal concentration (R2 = 0.049, R2 = 0.11, respectively). Conclusion: There is significant seasonal variation in total fungal concentration and concentration of select allergenic species. Indoor relative humidity and temperature may underlie these associations. © 2022 Elsevier Ltd |
Mycobiota and the contribution of yeasts in floor dust of 50 elementary schools characterized with sequencing internal transcribed spacer region of ribosomal DNA
Park JH , Lemons AR , Croston TL , Park Y , Roseman J , Green BJ , Cox-Ganser JM . Environ Sci Technol 2022 56 (16) 11493-11503 The assemblage of fungi including unicellular yeasts in schools is understudied. We conducted an environmental study to characterize fungal communities in classroom floor dust. We collected 500 samples from 50 elementary schools in Philadelphia, PA, and evaluated room dampness/mold conditions. Genomic DNA from dust was extracted for internal transcribed spacer 1 Illumina MiSeq sequencing to identify operational taxonomic units (OTUs) organized from DNA sequences. Differential abundance analyses were performed to examine significant differences in abundance among groups. We identified 724 genera from 1490 OTUs. The genus Epicoccum was not diverse but the most abundant (relative abundance = 18.9%). Fungi were less diverse but most dissimilar in composition in the most water-damaged classrooms compared to the least water-damaged, indicating differential effects of individual classroom water-damage on fungal compositions. We identified 62 yeast genera, representing 19.6% of DNA sequences. Cyberlindnera was the most abundant (6.1%), followed by Cryptococcus, Aureobasidium, Rhodotorula, and Candida. The average relative abundance of yeasts tended to increase with increasing dampness and mold score and was significantly (p-value = 0.048) higher in the most water-damaged classrooms (22.4%) than the least water-damaged classrooms (18.2%). Our study suggests the need for further research on the potential health effects associated with exposures to yeasts in schools. |
Reduction of exposure to simulated respiratory aerosols using ventilation, physical distancing, and universal masking.
Coyle JP , Derk RC , Lindsley WG , Boots T , Blachere FM , Reynolds JS , McKinney WG , Sinsel EW , Lemons AR , Beezhold DH , Noti JD . Indoor Air 2022 32 (2) e12987 To limit community spread of SARS-CoV-2, CDC recommends universal masking indoors, maintaining 1.8 m of physical distancing, adequate ventilation, and avoiding crowded indoor spaces. Several studies have examined the independent influence of each control strategy in mitigating transmission in isolation, yet controls are often implemented concomitantly within an indoor environment. To address the influence of physical distancing, universal masking, and ventilation on very fine respiratory droplets and aerosol particle exposure, a simulator that coughed and exhaled aerosols (the source) and a second breathing simulator (the recipient) were placed in an exposure chamber. When controlling for the other two mitigation strategies, universal masking with 3-ply cotton masks reduced exposure to 0.3-3 µm coughed and exhaled aerosol particles by >77% compared to unmasked tests, whereas physical distancing (0.9 or 1.8 m) significantly changed exposure to cough but not exhaled aerosols. The effectiveness of ventilation depended upon the respiratory activity, that is, coughing or breathing, as well as the duration of exposure time. Our results demonstrate that a layered mitigation strategy approach of administrative and engineering controls can reduce personal inhalation exposure to potentially infectious very fine respiratory droplets and aerosol particles within an indoor environment. |
Efficacy of Ventilation, HEPA Air Cleaners, Universal Masking, and Physical Distancing for Reducing Exposure to Simulated Exhaled Aerosols in a Meeting Room.
Coyle JP , Derk RC , Lindsley WG , Blachere FM , Boots T , Lemons AR , Martin SBJr , Mead KR , Fotta SA , Reynolds JS , McKinney WG , Sinsel EW , Beezhold DH , Noti JD . Viruses 2021 13 (12) There is strong evidence associating the indoor environment with transmission of SARS-CoV-2, the virus that causes COVID-19. SARS-CoV-2 can spread by exposure to droplets and very fine aerosol particles from respiratory fluids that are released by infected persons. Layered mitigation strategies, including but not limited to maintaining physical distancing, adequate ventilation, universal masking, avoiding overcrowding, and vaccination, have shown to be effective in reducing the spread of SARS-CoV-2 within the indoor environment. Here, we examine the effect of mitigation strategies on reducing the risk of exposure to simulated respiratory aerosol particles within a classroom-style meeting room. To quantify exposure of uninfected individuals (Recipients), surrogate respiratory aerosol particles were generated by a breathing simulator with a headform (Source) that mimicked breath exhalations. Recipients, represented by three breathing simulators with manikin headforms, were placed in a meeting room and affixed with optical particle counters to measure 0.3-3 µm aerosol particles. Universal masking of all breathing simulators with a 3-ply cotton mask reduced aerosol exposure by 50% or more compared to scenarios with simulators unmasked. While evaluating the effect of Source placement, Recipients had the highest exposure at 0.9 m in a face-to-face orientation. Ventilation reduced exposure by approximately 5% per unit increase in air change per hour (ACH), irrespective of whether increases in ACH were by the HVAC system or portable HEPA air cleaners. The results demonstrate that mitigation strategies, such as universal masking and increasing ventilation, reduce personal exposure to respiratory aerosols within a meeting room. While universal masking remains a key component of a layered mitigation strategy of exposure reduction, increasing ventilation via system HVAC or portable HEPA air cleaners further reduces exposure. |
Face mask fit modifications that improve source control performance.
Blachere FM , Lemons AR , Coyle JP , Derk RC , Lindsley WG , Beezhold DH , Woodfork K , Duling MG , Boutin B , Boots T , Harris JR , Nurkiewicz T , Noti JD . Am J Infect Control 2021 50 (2) 133-140 BACKGROUND: During the COVID-19 pandemic, face masks are used as source control devices to reduce the expulsion of respiratory aerosols from infected people. Modifications such as mask braces, earloop straps, knotting and tucking, and double masking have been proposed to improve mask fit however the data on source control are limited. METHODS: The effectiveness of mask fit modifications was determined by conducting fit tests on human subjects and simulator manikins and by performing simulated coughs and exhalations using a source control measurement system. RESULTS: Medical masks without modification blocked ≥56% of cough aerosols and ≥42% of exhaled aerosols. Modifying fit by crossing the earloops or placing a bracket under the mask did not increase performance, while using earloop toggles, an earloop strap, and knotting and tucking the mask increased performance. The most effective modifications for improving source control performance were double masking and using a mask brace. Placing a cloth mask over a medical mask blocked ≥85% of cough aerosols and ≥91% of exhaled aerosols. Placing a brace over a medical mask blocked ≥95% of cough aerosols and ≥99% of exhaled aerosols. CONCLUSIONS: Fit modifications can greatly improve the performance of face masks as source control devices for respiratory aerosols. |
Gaseous and particulate content of laser tattoo removal plume
Levin YS , Grant MP , Glassford E , Green BJ , Lemons AR , Avram MM . Dermatol Surg 2021 47 (8) 1071-1078 BACKGROUND: There is increasing awareness of the potential hazards of surgical plumes. The plume associated with laser tattoo removal remains uncharacterized. OBJECTIVE: To determine the gaseous, particulate, and microbiological content of the laser tattoo removal plume. MATERIALS AND METHODS: Air sampling was performed during laser tattoo removal from pig skin and from patients. Measurement of metals, volatile organic compounds (VOCs), carbon monoxide (CO), hydrogen sulfide (HS), and ultrafine particulates (UPs) as well as bacterial 16S ribosomal DNA sequencing were performed. RESULTS: Metals were identified in the plume from both pig and human skin. Volatile organic compounds were found at similar levels within and outside the treatment room. Several bacterial phyla were detected in the treatment room, but not outside. High levels of UPs were measured throughout the treatment room during tattoo removal from pig skin. Ultrafine particulates were detected at low levels in the room periphery during tattoo removal from human skin, but at higher levels in the immediate treatment zone. HS and CO were not detected. CONCLUSION: Metals, VOCs, HS, and CO were found at levels below applicable occupational exposure limits. The presence of bacteria is of uncertain significance, but may be hazardous. High levels of UPs require further investigation. |
Bacterial community assemblages in classroom floor dust of 50 public schools in a large city: characterization using 16S rRNA sequences and associations with environmental factors.
Park JH , Lemons AR , Roseman J , Green BJ , Cox-Ganser JM . Microbiome 2021 9 (1) 15 Characterizing indoor microbial communities using molecular methods provides insight into bacterial assemblages present in environments that can influence occupants' health. We conducted an environmental assessment as part of an epidemiologic study of 50 elementary schools in a large city in the northeastern USA. We vacuumed dust from the edges of the floor in 500 classrooms accounting for 499 processed dust aliquots for 16S Illumina MiSeq sequencing to characterize bacterial assemblages. DNA sequences were organized into operational taxonomic units (OTUs) and identified using a database derived from the National Center for Biotechnology Information. Bacterial diversity and ecological analyses were performed at the genus level. We identified 29 phyla, 57 classes, 148 orders, 320 families, 1193 genera, and 2045 species in 3073 OTUs. The number of genera per school ranged from 470 to 705. The phylum Proteobacteria was richest of all while Firmicutes was most abundant. The most abundant order included Lactobacillales, Spirulinales, and Clostridiales. Halospirulina was the most abundant genus, which has never been reported from any school studies before. Gram-negative bacteria were more abundant and richer (relative abundance = 0.53; 1632 OTUs) than gram-positive bacteria (0.47; 1441). Outdoor environment-associated genera were identified in greater abundance in the classrooms, in contrast to homes where human-associated bacteria are typically more abundant. Effects of school location, degree of water damage, building condition, number of students, air temperature and humidity, floor material, and classroom's floor level on the bacterial richness or community composition were statistically significant but subtle, indicating relative stability of classroom microbiome from environmental stress. Our study indicates that classroom floor dust had a characteristic bacterial community that is different from typical house dust represented by more gram-positive and human-associated bacteria. Health implications of exposure to the microbiomes in classroom floor dust may be different from those in homes for school staff and students. Video abstract. |
Inactivation of the multi-drug resistant pathogen Candida auris using ultraviolet germicidal irradiation (UVGI)
Lemons AR , McClelland TL , Martin SBJr , Lindsley WG , Green BJ . J Hosp Infect 2020 BACKGROUND: Candida auris, often a multi-drug resistant fungal pathogen, has become an emerging threat in healthcare settings around the world. Reliable disinfection protocols specifically designed to inactivate C. auris are essential, as many chemical disinfectants commonly used in healthcare settings have been shown to have variable efficacy at inactivating C. auris. AIM: Ultraviolet germicidal irradiation (UVGI) was investigated as a method to inactivate clinically relevant strains of C. auris. METHODS: Ten C. auris and two C. albicans isolates were exposed to ultraviolet (UV) energy to determine the UV dose required to inactivate each isolate. Using a UV reactor, each isolate (10(6) cells/mL) was exposed to 11 UV doses ranging from 10-150 mJ/cm(2) and then cultured to assess cell viability. FINDINGS: An exponential decay model was applied to each dose-response curve to determine inactivation rate constants for each isolate, which ranged from 0.108-0.176 cm(2)/mJ for C. auris and 0.239-0.292 cm(2)/mJ for C. albicans. As the model of exponential decay did not accurately estimate the dose beyond 99.9% inactivation, a logistic regression model was applied to better estimate the doses required for 99.999% inactivation. Using this model, significantly greater UV energy was required to inactivate C. auris (103 to 192 mJ/cm(2)) when compared to C. albicans (78 to 80 mJ/cm(2)). CONCLUSION: This study demonstrated UVGI as a feasible approach for inactivating C. auris, although variable susceptibility among isolates must be taken into account. This dose-response data is critical for recommending UVGI dosing strategies to be tested in healthcare settings. |
Cultivation and aerosolization of Stachybotrys chartarum for modeling pulmonary inhalation exposure
Lemons AR , Croston TL , Goldsmith WT , Barnes MA , Jaderson MA , Park JH , McKinney W , Beezhold DH , Green BJ . Inhal Toxicol 2019 31 1-11 Objective: Stachybotrys chartarum is a hydrophilic fungal species commonly found as a contaminant in water-damaged building materials. Although several studies have suggested that S. chartarum exposure elicits a variety of adverse health effects, the ability to characterize the pulmonary immune responses to exposure is limited by delivery methods that do not replicate environmental exposure. This study aimed to develop a method of S. chartarum aerosolization to better model inhalation exposures. Materials and methods: An acoustical generator system (AGS) was previously developed and utilized to aerosolize and deliver fungal spores to mice housed in a multi-animal nose-only exposure chamber. In this study, methods for cultivating, heat-inactivating, and aerosolizing two macrocyclic trichothecene-producing strains of S. chartartum using the AGS are described. Results and discussion: In addition to conidia, acoustical generation of one strain of S. chartarum resulted in the aerosolization of fungal fragments (<2 microm aerodynamic diameter) derived from conidia, phialides, and hyphae that initially comprised 50% of the total fungal particle count but was reduced to less than 10% over the duration of aerosolization. Acoustical generation of heat-inactivated S. chartarum did not result in a similar level of fragmentation. Delivery of dry, unextracted S. chartarum using these aerosolization methods resulted in pulmonary inflammation and immune cell infiltration in mice inhaling viable, but not heat-inactivated S. chartarum. Conclusions: These methods of S. chartarum growth and aerosolization allow for the delivery of fungal bioaerosols to rodents that may better simulate natural exposure within water-damaged indoor environments. |
Inhalation of Stachybotrys chartarum fragments induces pulmonary arterial remodeling
Croston TL , Lemons AR , Barnes MA , Goldsmith WT , Orandle MS , Nayak AP , Germolec DR , Green BJ , Beezhold DH . Am J Respir Cell Mol Biol 2019 62 (5) 563-576 Stachybotrys chartarum is a fungal contaminant within the built environment and a respiratory health concern in the United States. The objective of this study was to characterize the mechanisms influencing pulmonary immune responses to repeatedly inhaled S. chartarum. Groups of B6C3F1/N mice repeatedly inhaled viable trichothecene-producing S. chartarum conidia (Strain A or Strain B), heat-inactivated conidia, or HEPA-filtered air twice a week for 4 and 13 weeks. Strain A was found to produce higher amounts of respirable fragments compared to Strain B. Lung tissue, serum and bronchoalveolar lavage fluid (BALF) were collected at 24 and 48 hours following final exposure and processed for histology, flow cytometry, RNA, and proteomic analyses. At 4 weeks post-exposure, a Th2-mediated response was observed. After 13 weeks, a mixed T-cell response was observed following exposure to Strain A, compared to a Th2-mediated response following Strain B exposure. Following exposure, both strains induced pulmonary arterial remodeling at 13 weeks; however, Strain A-exposed mice progressed more quickly compared to Strain B-exposed mice. BALF was composed primarily of eosinophils, neutrophils, and macrophages. Both the immune response and the observed pulmonary arterial remodeling were supported by specific cellular, molecular, and proteomic profiles. The immunopathological responses occurred earlier in mice exposed to high fragment-producing Strain A. The rather striking induction of pulmonary remodeling by S. chartarum appears to be related to the presence of fungal fragments during exposure. |
Potential occupational and respiratory hazards in a Minnesota cannabis cultivation and processing facility
Couch JR , Grimes GR , Wiegand DM , Green BJ , Glassford EK , Zwack LM , Lemons AR , Jackson SR , Beezhold DH . Am J Ind Med 2019 62 (10) 874-882 BACKGROUND: Cannabis has been legalized in some form for much of the United States. The National Institute for Occupational Safety and Health (NIOSH) received a health hazard evaluation request from a Minnesota cannabis facility and their union to undertake an evaluation. METHODS: NIOSH representatives visited the facility in August 2016 and April 2017. Surface wipe samples were collected for analysis of delta-9 tetrahydrocannabinol (Delta9-THC), delta-9 tetrahydrocannabinol acid (Delta9-THCA), cannabidiol, and cannabinol. Environmental air samples were collected for volatile organic compounds (VOCs), endotoxins (limulus amebocyte lysate assay), and fungal diversity (NIOSH two-stage BC251 bioaerosol sampler with internal transcribed spacer region sequencing analysis). RESULTS: Surface wipe samples identified Delta9-THC throughout the facility. Diacetyl and 2,3-pentanedione were measured in initial VOC screening and subsequent sampling during tasks where heat transference was greatest, though levels were well below the NIOSH recommended exposure limits. Endotoxin concentrations were highest during processing activities, while internal transcribed spacer region sequencing revealed that the Basidiomycota genus, Wallemia, had the highest relative abundance. CONCLUSIONS: To the authors' knowledge, this is the first published report of potential diacetyl and 2,3-pentanedione exposure in the cannabis industry, most notably during cannabis decarboxylation. Endotoxin exposure was elevated during grinding, indicating that this is a potentially high-risk task. The findings indicate that potential health hazards of significance are present during cannabis processing, and employers should be aware of potential exposures to VOCs, endotoxin, and fungi. Further research into the degree of respiratory and dermal hazards and resulting health effects in this industry is recommended. |
Endotoxin exposures during harvesting and processing cannabis at an outdoor cannabis farm
Couch JR , Burton NC , Victory KR , Green BJ , Lemons AR , Nayak AP , Beezhold DH . Aerobiologia 2019 35 (2) 367-371 Legalization of medicinal and recreational cannabis use in numerous states within the USA has resulted in the increased commercial cultivation of cannabis. Outdoor cannabis farming operations present a variety of potential physical, chemical, and biological hazards that currently remain uncharacterized. Worker exposures to endotoxins were evaluated at an outdoor US cannabis farm during harvesting and processing activities. Endotoxin area air sample concentrations ranged from below the limit of detection to 15 endotoxin units per cubic meter (EU/m3). Endotoxin breathing zone measurements (2.8–37 EU/m3) were below the Dutch Expert Committee on Occupational Safety occupational exposure limit of 90 /m3. During confidential medical interviews, no adverse health effects were reported by workers while harvesting or processing cannabis. Further endotoxin exposure assessments should be performed especially in larger, indoor cannabis operations where a confined environment may result in higher endotoxin exposures than observed in this outdoor environment. |
Alternaria is associated with asthma symptoms and exhaled NO among NYC children
Soffer N , Green BJ , Acosta L , Divjan A , Sobek E , Lemons AR , Rundle AG , Jacobson JS , Goldstein IF , Miller RL , Perzanowsk MS . J Allergy Clin Immunol 2018 142 (4) 1366-1368 e10 Among NYC children, Alternaria sensitization, even at low IgE concentrations, was associated with asthma morbidity. Domestic Alternaria exposure, which was common, was associated with exhaled NO, specifically among children with higher neighborhood-level combustion air pollution. |
Collection and Extraction of Occupational Air Samples for Analysis of Fungal DNA.
Lemons AR , Lindsley WG , Green BJ . J Vis Exp 2018 (135) Traditional methods of identifying fungal exposures in occupational environments, such as culture and microscopy-based approaches, have several limitations that have resulted in the exclusion of many species. Advances in the field over the last two decades have led occupational health researchers to turn to molecular-based approaches for identifying fungal hazards. These methods have resulted in the detection of many species within indoor and occupational environments that have not been detected using traditional methods. This protocol details an approach for determining fungal diversity within air samples through genomic DNA extraction, amplification, sequencing, and taxonomic identification of fungal internal transcribed spacer (ITS) regions. ITS sequencing results in the detection of many fungal species that are either not detected or difficult to identify to species level using culture or microscopy. While these methods do not provide quantitative measures of fungal burden, they offer a new approach to hazard identification and can be used to determine overall species richness and diversity within an occupational environment. |
Characterization of fungi in office dust: comparing results of microbial secondary metabolites, fungal ITS region sequencing, viable culture, and other microbial indices
Park JH , Sulyok M , Lemons AR , Green BJ , Cox-Ganser JM . Indoor Air 2018 Recent developments in molecular and chemical methods have enabled the analysis of fungal DNA and secondary metabolites, often produced during fungal growth, in environmental samples. We compared three fungal analytical methods by analyzing floor dust samples collected from an office building for fungi using viable culture, internal transcribed spacer (ITS) sequencing, and secondary metabolites using liquid chromatography-tandem mass spectrometry. Of the 32 metabolites identified, 29 had a potential link to fungi with levels ranging from 0.04 (minimum for alternariol monomethylether) to 5,700 ng/g (maximum for neoechinulin A). The number of fungal metabolites quantified per sample ranged from eight to sixteen (average=13/sample). We identified 216 fungal operational taxonomic units (OTUs) with the number per sample ranging from six to twenty-nine (average=18/sample). We identified 37 fungal species using culture and the number per sample ranged from two to thirteen (average=eight/sample). Agreement in identification between ITS sequencing and culturing was weak (kappa=-0.12-0.27). The number of cultured fungal species poorly correlated with OTUs, which did not correlate with the number of metabolites. These suggest that using multiple measurement methods may provide an improved understanding of fungal exposures in indoor environments and that secondary metabolites may be considered as an additional source of exposure. This article is protected by copyright. All rights reserved. |
Aspergillus fumigatus viability drives allergic responses to inhaled conidia
Nayak AP , Croston TL , Lemons AR , Goldsmith WT , Marshall NB , Kashon ML , Germolec DR , Beezhold DH , Green BJ . Ann Allergy Asthma Immunol 2018 121 (2) 200-210 e2 BACKGROUND: Aspergillus fumigatus induced allergic airway disease has been shown to involve conidial germination in vivo but the immunological mechanisms remain uncharacterized. OBJECTIVE: A subchronic murine exposure model was used to examine the immunological mediators that are regulated in response to either culturable or non-culturable A. fumigatus conidia. METHODS: Female B6C3F1/N mice were repeatedly dosed via inhalation with 1 x 105 viable or heat inactivated conidia (HIC), twice a week for 13 weeks (26 exposures). Control mice inhaled HEPA-filtered air. The influence of A. fumigatus conidial germination on the pulmonary immunopathological outcomes was evaluated by flow cytometry analysis of cellular infiltration in the airways, assessment of lung mRNA expression, and quantitative proteomics and histopathology of whole lung tissue. RESULTS: Repeated inhalation of viable conidia, but not HIC, resulted in allergic inflammation marked by vascular remodeling, extensive eosinophilia, and accumulation of alternatively activated macrophages (AAMs) in the murine airways. More specifically, mice that inhaled viable conidia resulted in a mixed TH1 and TH2 (IL-13) cytokine response. Recruitment of eosinophils corresponded with increased Ccl11 transcripts. Furthermore, genes associated with M2 or alternatively activated macrophage polarization (e.g. Arg1, Chil3 and Retnla) were significantly upregulated in viable A. fumigatus exposed mice. In mice inhaling HIC, CD4+ T cells expressing IFN-gamma (TH1) dominated the lymphocytic infiltration. Quantitative proteomics of the lung revealed metabolic reprogramming accompanied by mitochondrial dysfunction and endoplasmic reticulum stress stimulated by oxidative stress from repetitive microbial insult. CONCLUSION: Our studies demonstrate that A. fumigatus conidial viability in vivo is critical to the immunopathological presentation of chronic fungal allergic disease. |
MicroRNA regulation of host immune responses following fungal exposure
Croston TL , Lemons AR , Beezhold DH , Green BJ . Front Immunol 2018 9 170 Fungal bioaerosols are ubiquitous in the environment and human exposure can result in a variety of health effects ranging from systemic, subcutaneous, and cutaneous infections to respiratory morbidity including allergy, asthma, and hypersensitivity pneumonitis. Recent research has focused on the role of microRNAs (miRNAs) following fungal exposure and is overlooked, yet important, group of regulators capable of influencing fungal immune responses through a variety of cellular mechanisms. These small non-coding ribose nucleic acids function to regulate gene expression at the post-transcriptional level and have been shown to participate in multiple disease pathways including cancer, heart disease, apoptosis, as well as immune responses to microbial hazards and occupational allergens. Recent animal model studies have characterized miRNAs following the exposure to inflammatory stimuli. Studies focused on microbial exposure, including bacterial infections, as well as exposure to different allergens have shown miRNAs, such as miR-21, miR-146, miR-132, miR-155, and the let-7 family members, to be involved in immune and inflammatory responses. Interestingly, the few studies have assessed that the miRNA profiles following fungal exposure have identified the same critical miRNAs that have been characterized in other inflammatory-mediated and allergy-induced experimental models. Review of available in vitro, animal and human studies of exposures to Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Paracoccidioides brasiliensis, and Stachybotrys chartarum identified several miRNAs that were shared between responses to these species including miR-125 a/b (macrophage polarization/activation), miR-132 [toll-like receptor (TLR)2-mediated signaling], miR-146a (TLR mediated signaling, alternative macrophage activation), and miR-29a/b (natural killer cell function, C-leptin signaling, inhibition of Th1 immune response). Although these datasets provide preliminary insight into the role of miRNAs in fungal exposed models, interpretation of miRNA datasets can be challenging for researchers. To assist in navigating this rapidly evolving field, the aim of this review is to describe miRNAs in the framework of host recognition mechanisms and provide initial insight into the regulatory pathways in response to fungal exposure. |
Microbial hazards during harvesting and processing at an outdoor United States cannabis farm.
Green BJ , Couch JR , Lemons AR , Burton NC , Victory KR , Nayak AP , Beezhold DH . J Occup Environ Hyg 2018 15 (5) 0 Cannabis cultivation is an emerging industry within the United States. Organic dust derived in part from naturally occurring microorganisms is known to cause byssinosis in the hemp industry. In this pilot study, bacteria and fungi encountered by workers at an outdoor cannabis farm that utilized organic practices were elucidated by 1625% shaded blockS ribosomal RNA (rRNA) and Internal Transcribed Spacer (ITS) region sequencing, respectively. Area (n = 14) and personal air samples (n = 12) were collected during harvesting and processing activities. 1625% shaded blockS rRNA and ITS regions of extracted bacterial and fungal genomic DNA were amplified and sequenced using Sanger sequencing. Bacterial sequencing resolved 1077 sequences that were clustered into 639 operational taxonomic units (OTUs) and predominantly placed in the phylum, Actinobacteria (46%). Personal air samples revealed higher bacterial and Actinobacteria diversity compared to outdoor area samples collected within the facility (p<0.05). A high degree of dissimilarity between bacteria was identified within and between samples. Fungal sequences (n = 985) were identified and predominantly clustered in the phylum Ascomycota (53%). Of the 216 fungal OTUs elucidated, the cannabis plant pathogenic species, Botrytis cinerea, was the most prevalent and accounted for 34% of all fungal sequences. The relative abundance of B. cinerea was highest in personal air samples (59%) compared to area samples collected in the drying room (19%), greenhouse (18%) and outdoor environment (6%). There was 49% sample similarity between fungi identified within personal air samples, but higher dissimilarity coefficients were observed within and between greenhouse, drying room, and outdoor area air samples. The results of this pilot study suggest that the cannabis farm workers are potentially exposed to Actinobacteria as well as the cannabis plant pathogen, B. cinerea during harvesting, bud stripping, and hand trimming processes. |
Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States.
Lemons AR , Hogan MB , Gault RA , Holland K , Sobek E , Olsen-Wilson KA , Park Y , Park JH , Gu JK , Kashon ML , Green BJ . Environ Sci Process Impacts 2017 19 (2) 101-110 Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study. Air samples were collected from the child's bedroom for genomic DNA extraction and metagenomic analysis of bacteria and fungi using the Illumina MiSeq sequencing platform. The analysis of bacterial populations revealed no major differences between EC and AC sampling environments. The fungal populations observed in EC homes differed from AC homes. The most prevalent species discovered in AC environments belonged to the genera Cryptococcus (20%) and Aspergillus (20%). In contrast, the most common fungi identified in EC homes belonged to the order Pleosporales and included Alternaria alternata (32%) and Phoma spp. (22%). The variations in fungal populations provide preliminary evidence of the microbial burden children may be exposed to within EC environments in this region. |
Assessment of fungal diversity in a water-damaged office building.
Green BJ , Lemons AR , Park Y , Cox-Ganser JM , Park JH . J Occup Environ Hyg 2016 14 (4) 285-293 Recent studies have described fungal communities in indoor environments using gene sequencing-based approaches. In this study, dust-borne fungal communities were elucidated from a water-damaged office building located in the northeastern region of the United States using internal transcribed spacer (ITS) rRNA gene sequencing. Genomic DNA was extracted from 5 mg of floor dust derived from 22 samples collected from either the lower floors (n = 8) or a top floor (n = 14) of the office building. ITS gene sequencing resolved a total of 933 ITS sequences and was clustered into 216 fungal operational taxonomic units (OTUs). Analysis of fungal OTUs at the 97% similarity threshold showed a difference between the lower and top floors that was marginally significant (p = 0.049). Species richness and diversity indices were reduced in the lower floor samples compared to the top floor samples and there was a high degree of compositional dissimilarity within and between the two different areas within the building. Fungal OTUs were placed in the phyla Ascomycota (55%), Basidiomycota (41%), Zygomycota (3%), Glomeromycota (0.4%), Chytridiomycota (0.3%) and unassigned fungi (0.5%). The Ascomycota classes with the highest relative abundances included the Dothideomycetes (30%) and Eurotiomycetes (16%). The Basidiomycota consisted of the classes Ustilaginomycetes (14%), Tremellomycetes (11%), and Agaricomycetes (8%). Sequence reads derived from the plant pathogen Ustilago syntherismae were the most abundant in the analysis as were obligate Basidiomycota yeast species that accounted for 12% and 11% of fungal ITS sequences, respectively. ITS gene sequencing provides additional insight into the diversity of fungal OTUs. These data further highlight the contribution of fungi placed in the phylum Basidiomycota, obligate yeasts, as well as xerophilic species that are typically not resolved using traditional culture methods. |
Investigating a persistent odor at an aircraft seat manufacturer
Broadwater K , de Perio MA , Roberts J , Burton NC , Lemons AR , Green BJ , Brueck SE . J Occup Environ Hyg 2016 13 (10) D159-65 An aircraft seat manufacturing company requested a NIOSH health hazard evaluation to help identify a strong odor that had persisted throughout the facility for over a year. Employees reported experiencing health effects thought to be related to the odor. We collected and analyzed area air samples for volatile organic compounds, endotoxin, bacterial and fungal metagenome, and metalworking fluid aerosol. Bulk metalworking fluid samples were analyzed for endotoxin, bacterial and fungal metagenome, and viable bacteria and fungus. We also evaluated the building ventilation systems and water diversion systems. Employees underwent confidential medical interviews about work practices, medical history, and health concerns. Based on our analyses, the odor was likely 2-methoxy-3,5-dimethylpyrazine. This pyrazine was found in air samples across the facility and originated from bacteria in the metalworking fluid. We did not identify bacteria known to produce the compound but bacteria from the same Proteobacteria order were found as well as bacteria from orders known to produce other pyrazines. Chemical and biological contaminants and odors could have contributed to health symptoms reported by employees, but it is likely that the symptoms were caused by several factors. We provided several recommendations to eliminate the odor including washing and disinfecting the metalworking machines and metalworking fluid recycling equipment, discarding all used metalworking fluid, instituting a metalworking fluid maintenance program at the site, and physically isolating the metalworking department from other departments. |
Influence of Aspergillus fumigatus conidia viability on murine pulmonary microRNA and mRNA expression following subchronic inhalation exposure.
Croston TL , Nayak AP , Lemons AR , Goldsmith WT , Gu JK , Germolec DR , Beezhold DH , Green BJ . Clin Exp Allergy 2016 46 (10) 1315-27 BACKGROUND: Personal exposure to fungal bioaerosols derived from contaminated building materials or agricultural commodities may induce or exacerbate a variety of adverse health effects. The genomic mechanisms that underlie pulmonary immune responses to fungal bioaerosols have remained unclear. OBJECTIVE: The impact of fungal viability on the pulmonary microRNA and messenger RNA profiles that regulate murine immune responses was evaluated following subchronic inhalation exposure to Aspergillus fumigatus conidia. METHODS: Three groups of naive B6C3F1/N mice were exposed via nose-only inhalation to A. fumigatus viable conidia, heat-inactivated conidia, or HEPA-filtered air twice a week for 13 weeks. Total RNA was isolated from whole lung 24 and 48 hours post final exposure and was further processed for gene expression and microRNA array analysis. The molecular network pathways between viable and heat-inactivated conidia groups were evaluated. RESULTS: Comparison of datasets revealed increased Il4, Il13, and Il33 expression in mice exposed to viable versus heat-inactivated conidia. Of 415 microRNAs detected, approximately 50% were altered in mice exposed to viable versus heat-inactivated conidia 48 hours post exposure. Significantly downregulated (P < 0.05) miR-29a-3p was predicted to regulate TGF-beta3 and Clec7a, genes involved in innate responses to viable A. fumigatus. Also significantly downregulated (P < 0.05), miR-23b-3p regulates genes involved in pulmonary IL-13 and IL-33 responses and SMAD2, downstream of TGF-beta signaling. Using Ingenuity Pathway Analysis, a novel interaction was identified between viable conidia and SMAD2/3. CONCLUSION AND CLINICAL RELEVANCE: Examination of the pulmonary genetic profiles revealed differentially expressed genes and microRNAs following subchronic inhalation exposure to A. fumigatus. MicroRNAs regulating genes involved in the pulmonary immune responses were those with the greatest fold change. Specifically, germinating A. fumigatus conidia were associated with Clec7a and were predicted to interact with Il13 and Il33. Furthermore, altered microRNAs may serve as potential biomarkers to evaluate fungal exposure. |
The Influence of Diisocyanate Antigen Preparation Methodology on Monoclonal and Serum Antibody Recognition
Hagerman LM , Law BF , Bledsoe TA , Hettick JM , Kashon ML , Lemons AR , Wisnewski AV , Siegel PD . J Occup Environ Hyg 2016 13 (11) 829-39 Exposure to diisocyanates (dNCOs), such as methylene diphenyl diisocyanate (MDI) can cause occupational asthma (OA). Currently, lab tests for dNCO specific IgE are specific, but not sensitive, which limits their utility in diagnosing dNCO asthma. This may be due to variable preparation and poor characterization of the standard antigens utilized in these assays. The aim of this study was to produce and characterize a panel of antigens prepared using three different commonly employed methods and one novel method. The conjugates were examined for recognition by anti-MDI monoclonal antibodies (mAbs) in varying enzyme linked immunosorbant assay (ELISA) formats, extent of crosslinking, total amount of MDI, the sites of MDI conjugation, relative shape/charge, and reactivity with human serum with antibodies from sensitized, exposed workers. Results indicate that while there are minimal differences in the total amount of MDI conjugated, the extent of crosslinking, and the conjugation sites, there are significant differences in the recognition of differently prepared conjugates by mAbs. Native and denaturing polyacrylamide gel electrophoresis demonstrate differences in the mobility of different conjugates, indicative of structural changes that are likely important for antigenicity. While mAbs exhibited differential binding to different conjugates, polyclonal serum antibodies from MDI exposed workers exhibited equivalent binding to different conjugates by ELISA. While differences in the recognition of the different conjugates exist by mAb detection, differences in antigenicity could not be detected using human serum from MDI-sensitized individuals. Thus, although dNCO conjugate preparation can, depending on the immunoassay platform, influence binding of specific antibody clones, serologic detection of the dNCO-exposure-induced polyclonal antibody response may be less sensitive to these differences. |
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