Last data update: Mar 21, 2025. (Total: 48935 publications since 2009)
Records 1-30 (of 30 Records) |
Query Trace: Black CM[original query] |
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Shift work influences the outcomes of Chlamydia infection and pathogenesis
Lundy SR , Richardson S , Ramsey A , Ellerson D , Fengxia Y , Onyeabor S , Kirlin W , Thompson W , Black CM , DeBruyne JP , Davidson AJ , Immergluck LC , Blas-Machado U , Eko FO , Igietseme JU , He Q , Omosun YO . Sci Rep 2020 10 (1) 15389 Shift work, performed by approximately 21 million Americans, is irregular or unusual work schedule hours occurring after 6:00 pm. Shift work has been shown to disrupt circadian rhythms and is associated with several adverse health outcomes and chronic diseases such as cancer, gastrointestinal and psychiatric diseases and disorders. It is unclear if shift work influences the complications associated with certain infectious agents, such as pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility resulting from genital chlamydial infection. We used an Environmental circadian disruption (ECD) model mimicking circadian disruption occurring during shift work, where mice had a 6-h advance in the normal light/dark cycle (LD) every week for a month. Control group mice were housed under normal 12/12 LD cycle. Our hypothesis was that compared to controls, mice that had their circadian rhythms disrupted in this ECD model will have a higher Chlamydia load, more pathology and decreased fertility rate following Chlamydia infection. Results showed that, compared to controls, mice that had their circadian rhythms disrupted (ECD) had higher Chlamydia loads, more tissue alterations or lesions, and lower fertility rate associated with chlamydial infection. Also, infected ECD mice elicited higher proinflammatory cytokines compared to mice under normal 12/12 LD cycle. These results imply that there might be an association between shift work and the increased likelihood of developing more severe disease from Chlamydia infection. |
EGFR and TGF-beta signaling pathways cooperate to mediate Chlamydia pathogenesis
Igietseme JU , Partin J , George Z , Omosun Y , Goldstein J , Joseph K , Ellerson D , Eko FO , Pohl J , Bandea C , Black CM . Infect Immun 2020 88 (4) Human genital Chlamydia infection is a major public health concern due to the serious reproductive system complications. Chlamydia binds several receptor tyrosine kinases (RTKs) on host cells, including the epidermal growth factor receptor (EGFR) and activates cellular signaling cascades for host invasion, cytoskeletal remodeling, optimal inclusion development, and induction of pathogenic epithelial-mesenchyme transition (EMT). Chlamydia also upregulates TGF-beta expression whose signaling pathway synergizes with the EGFR cascade, but its role in infectivity, inclusions and EMT induction is unknown. We hypothesized that the EGFR and TGF-beta signaling pathways cooperate during chlamydial infection for optimal inclusion development and stable EMT induction. The results revealed that Chlamydia upregulated TGF-beta expression as early as 6 h post-infection of epithelial cells and stimulated both the EGFR and TGF-beta signaling pathways. Inhibition of either the EGFR or TGF-betaR1 signaling substantially reduced inclusions development; however, the combined inhibition of both EGFR and TGF-betaR1 signaling reduced inclusions by over 90% and prevented EMT induction. Importantly, EGFR inhibition suppressed TGF-beta expression, and an inhibitory thrombospondin-1 (Tsp1)-based peptide inhibited chlamydia-induced EMT, revealing a major source of active TGF-betaduring infection. Finally, TGF-betaR signaling inhibition suppressed the expression of transforming acidic coiled-coil protein-3 (TACC3) that stabilizes EGFR signaling, suggesting a reciprocal regulation between TGF-beta and EGFR signaling during chlamydial infection. Thus, RTK-mediated host invasion by chlamydia upregulated TGF-beta expression and signaling, which cooperated with other cellular signaling cascades and cytoskeletal remodeling to support optimal inclusion development and EMT induction. The finding may provide new targets for chlamydial disease biomarkers and prevention. |
Effect of time of day of infection on chlamydia infectivity and pathogenesis
Lundy SR , Ahmad T , Simoneaux T , Benyeogor I , Robinson Y , George Z , Ellerson D , Kirlin W , Omosun T , Eko FO , Black CM , Blas-Machado U , DeBruyne JP , Igietseme JU , He Q , Omosun YO . Sci Rep 2019 9 (1) 11405 Genital chlamydia infection in women causes complications such as pelvic inflammatory disease and tubal factor infertility, but it is unclear why some women are more susceptible than others. Possible factors, such as time of day of chlamydia infection on chlamydial pathogenesis has not been determined. We hypothesised that infections during the day, will cause increased complications compared to infections at night. Mice placed under normal 12:12 light: dark (LD) cycle were infected intravaginally with Chlamydia muridarum either at zeitgeber time 3, ZT3 and ZT15. Infectivity was monitored by periodic vaginal swabs and chlamydiae isolation. Blood and vaginal washes were collected for host immunologic response assessments. The reproductive tracts of the mice were examined histopathologically, and fertility was determined by embryo enumeration after mating. Mice infected at ZT3 shed significantly more C. muridarum than mice infected at ZT15. This correlated with the increased genital tract pathology observed in mice infected at ZT3. Mice infected at ZT3 were less fertile than mice infected at ZT15. The results suggest that the time of day of infection influences chlamydial pathogenesis, it indicates a possible association between complications from chlamydia infection and host circadian clock, which may lead to a better understanding of chlamydial pathogenesis. |
A unique insight into the MiRNA profile during genital chlamydial infection.
Benyeogor I , Simoneaux T , Wu Y , Lundy S , George Z , Ryans K , McKeithen D , Pais R , Ellerson D , Lorenz WW , Omosun T , Thompson W , Eko FO , Black CM , Blas-Machado U , Igietseme JU , He Q , Omosun Y . BMC Genomics 2019 20 (1) 143 ![]() ![]() BACKGROUND: Genital C. trachomatis infection may cause pelvic inflammatory disease (PID) that can lead to tubal factor infertility (TFI). Understanding the pathogenesis of chlamydial complications including the pathophysiological processes within the female host genital tract is important in preventing adverse pathology. MicroRNAs regulate several pathophysiological processes of infectious and non-infectious etiologies. In this study, we tested the hypothesis that the miRNA profile of single and repeat genital chlamydial infections will be different and that these differences will be time dependent. Thus, we analyzed and compared differentially expressed mice genital tract miRNAs after single and repeat chlamydia infections using a C. muridarum mouse model. Mice were sacrificed and their genital tract tissues were collected at 1, 2, 4, and 8 weeks after a single and repeat chlamydia infections. Histopathology, and miRNA sequencing were performed. RESULTS: Histopathology presentation showed that the oviduct and uterus of reinfected mice were more inflamed, distended and dilated compared to mice infected once. The miRNAs expression profile was different in the reproductive tissues after a reinfection, with a greater number of miRNAs expressed after reinfection. Also, the number of miRNAs expressed each week after chlamydia infection and reinfection varied, with weeks eight and one having the highest number of differentially expressed miRNAs for chlamydia infection and reinfection respectively. Ten miRNAs; mmu-miR-378b, mmu-miR-204-5p, mmu-miR-151-5p, mmu-miR-142-3p, mmu-miR-128-3p, mmu-miR-335-3p, mmu-miR-195a-3p, mmu-miR-142-5p, mmu-miR-106a-5p and mmu-miR-92a-3p were common in both primary chlamydia infection and reinfection. Pathway analysis showed that, amongst other functions, the differentially regulated miRNAs control pathways involved in cellular and tissue development, disease conditions and toxicity. CONCLUSIONS: This study provides insights into the changes in miRNA expression over time after chlamydia infection and reinfection, as well as the pathways they regulate to determine pathological outcomes. The miRNAs networks generated in our study shows that there are differences in the focus molecules involved in significant biological functions in chlamydia infection and reinfection, implying that chlamydial pathogenesis occurs differently for each type of infection and that this could be important when determining treatments regime and disease outcome. The study underscores the crucial role of host factors in chlamydia pathogenesis. |
The molecular mechanism of induction of unfolded protein response by Chlamydia
George Z , Omosun Y , Azenabor AA , Goldstein J , Partin J , Joseph K , Ellerson D , He Q , Eko F , McDonald MA , Reed M , Svoboda P , Stuchlik O , Pohl J , Lutter E , Bandea C , Black CM , Igietseme JU . Biochem Biophys Res Commun 2019 508 (2) 421-429 The unfolded protein response (UPR) contributes to chlamydial pathogenesis, as a source of lipids and ATP during replication, and for establishing the initial anti-apoptotic state of host cell that ensures successful inclusion development. The molecular mechanism(s) of UPR induction by Chlamydia is unknown. Chlamydia use type III secretion system (T3SS) effector proteins (e.g, the Translocated Actin-Recruiting Phosphoprotein (Tarp) to stimulate host cell's cytoskeletal reorganization that facilitates invasion and inclusion development. We investigated the hypothesis that T3SS effector-mediated assembly of myosin-II complex produces activated non-muscle myosin heavy chain II (NMMHC-II), which then binds the UPR master regulator (BiP) and/or transducers to induce UPR. Our results revealed the interaction of the chlamydial effector proteins (CT228 and Tarp) with components of the myosin II complex and UPR regulator and transducer during infection. These interactions caused the activation and binding of NMMHC-II to BiP and IRE1alpha leading to UPR induction. In addition, specific inhibitors of myosin light chain kinase, Tarp oligomerization and myosin ATPase significantly reduced UPR activation and Chlamydia replication. Thus, Chlamydia induce UPR through T3SS effector-mediated activation of NMMHC-II components of the myosin complex to facilitate infectivity. The finding provides greater insights into chlamydial pathogenesis with the potential to identify therapeutic targets and formulations. |
Future of human Chlamydia vaccine: Potential of self-adjuvanting biodegradable nanoparticles as safe vaccine delivery vehicles
Sahu R , Verma R , Dixit S , Igietseme JU , Black CM , Duncan S , Singh SR , Dennis VA . Expert Rev Vaccines 2018 17 (3) 217-227 INTRODUCTION: There is a persisting global burden and considerable public health challenge by the plethora of ocular, genital and respiratory diseases caused by members of the Gram-negative bacteria of the genus Chlamydia. The major diseases are conjunctivitis and blinding trachoma, non-gonococcal urethritis, cervicitis, pelvic inflammatory disease, ectopic pregnancy, tubal factor infertility, and interstitial pneumonia. The failures in screening and other prevention programs led to the current medical opinion that an efficacious prophylactic vaccine is the best approach to protect humans from chlamydial infections. Unfortunately, there is no human Chlamydia vaccine despite successful veterinary vaccines. A major challenge has been the effective delivery of vaccine antigens to induce safe and effective immune effectors to confer long-term protective immunity. The dawn of the era of biodegradable polymeric nanoparticles and the adjuvanted derivatives may accelerate the realization of the dream of human vaccine in the foreseeable future. Areas covered: This review focuses on the current status of human chlamydial vaccine research, specifically the potential of biodegradable polymeric nanovaccines to provide efficacious Chlamydia vaccines in the near future. Expert commentary: The safety of biodegradable polymeric nanoparticles-based experimental vaccines with or without adjuvants and the array of available chlamydial vaccine candidates would suggest that clinical trials in humans may be imminent. Also, the promising results from vaccine testing in animal models could lead to human vaccines against trachoma and reproductive disease simultaneously. |
The emerging role of ASC in dendritic cell metabolism during Chlamydia infection
McKeithen DN , Omosun YO , Ryans K , Mu J , Xie Z , Simoneaux T , Blas-Machado U , Eko FO , Black CM , Igietseme JU , He Q . PLoS One 2017 12 (12) e0188643 Chlamydia trachomatis is a bacterial agent that causes sexually transmitted infections worldwide. The regulatory functions of dendritic cells (DCs) play a major role in protective immunity against Chlamydia infections. Here, we investigated the role of ASC in DCs metabolism and the regulation of DCs activation and function during Chlamydia infection. Following Chlamydia stimulation, maturation and antigen presenting functions were impaired in ASC-/- DCs compared to wild type (WT) DCs, in addition, ASC deficiency induced a tolerant phenotype in Chlamydia stimulated DCs. Using real-time extracellular flux analysis, we showed that activation in Chlamydia stimulated WT DCs is associated with a metabolic change in which mitochondrial oxidative phosphorylation (OXPHOS) is inhibited and the cells become committed to utilizing glucose through aerobic glycolysis for differentiation and antigen presenting functions. However, in ASC-/- DCs Chlamydia-induced metabolic change was prevented and there was a significant effect on mitochondrial morphology. The mitochondria of Chlamydia stimulated ASC-/- DCs had disrupted cristae compared to the normal narrow pleomorphic cristae found in stimulated WT DCs. In conclusion, our results suggest that Chlamydia-mediated activation of DCs is associated with a metabolic transition in which OXPHOS is inhibited, thereby dedicating the DCs to aerobic glycolysis, while ASC deficiency disrupts DCs function by inhibiting the reprogramming of DCs metabolism within the mitochondria, from glycolysis to electron transport chain. |
Molecular pathogenesis of chlamydia disease complications: Epithelial-mesenchyme transition and fibrosis
Igietseme JU , Omosun Y , Nagy T , Stuchlik O , Reed MS , He Q , Partin J , Joseph K , Ellerson D , George Z , Goldstein J , Eko FO , Bandea C , Pohl J , Black CM . Infect Immun 2017 86 (1) The reproductive system complications of genital chlamydial infection include fallopian tube fibrosis and tubal factor infertility. However the molecular pathogenesis of these complications remain poorly understood. The induction of pathogenic epithelial-Mesenchyme Transition (EMT) through miRNA dysregulation was recently proposed as the pathogenic basis of chlamydial complications. Focusing on fibrogenesis, we investigated the hypothesis that chlamydial-induced fibrosis is caused by EMT-driven generation of myofibroblasts, the effector cells of fibrosis that produce excessive extracellular matrix (ECM) proteins. The results revealed that the targets of a major category of altered miRNAs during chlamydial infection are key components of the pathophysiological process of fibrogenesis; these target molecules include collagen types I, III and IV, TGF-beta, TGF-betaR1, the connective tissue growth factor (CTGF), E-cadherin, SRY-Box 7 (SOX7), and nuclear NFAT kinase dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1a (Dyrk1a). Chlamydial induction of EMT resulted in the generation of alpha-smooth muscle actin (alpha-SMA)-positive myofibroblasts that produced ECM proteins, including collagen type I, III and fibronectin. Furthermore, the inhibition of EMT prevented the generation of myofibroblasts and production of ECM proteins during chlamydial infection. These findings may provide useful avenues for targeting EMT or specific components of the EMT pathways as a therapeutic intervention strategy to prevent chlamydial-related complications. |
The roles of unfolded protein response pathways in chlamydia pathogenesis
George Z , Omosun Y , Azenabor AA , Partin J , Joseph K , Ellerson D , He Q , Eko F , Bandea C , Svoboda P , Pohl J , Black CM , Igietseme JU . J Infect Dis 2017 215 (3) 456-465 Chlamydia is an obligate intracellular bacterium that relies on host cells for essential nutrients and adenosine triphosphate (ATP) for a productive infection. Although the unfolded protein response (UPR) plays a major role in certain microbial infectivity, its role in chlamydial pathogenesis is unknown. We hypothesized that Chlamydia induces UPR and exploits it to upregulate host cell uptake and metabolism of glucose, production of ATP, phospholipids, and other molecules required for its replicative development and host survival. Using a combination of biochemical and pathway inhibition assays, we showed that the 3 UPR pathway transducers-protein kinase RNA-activated (PKR)-like ER kinase (PERK), inositol-requiring enzyme-1alpha (IRE1alpha), and activating transcription factor-6alpha (ATF6alpha)-were activated during Chlamydia infection. The kinase activity of PERK and ribonuclease (RNase) of IRE1alpha mediated the upregulation of hexokinase II and production of ATP via substrate-level phosphorylation. In addition, the activation of PERK and IRE1alpha promoted autophagy formation and apoptosis resistance for host survival. Moreover, the activation of IRE1alpha resulted in the generation of spliced X-box binding protein 1 (sXBP1) and upregulation of lipid production. The vital role of UPR pathways in Chlamydia development and pathogenesis could lead to the identification of potential molecular targets for therapeutics against Chlamydia. |
The immunoregulatory role of alpha enolase in dendritic cell function during Chlamydia infection.
Ryans K , Omosun Y , McKeithen DN , Simoneaux T , Mills CC , Bowen N , Eko FO , Black CM , Igietseme JU , He Q . BMC Immunol 2017 18 (1) 27 ![]() BACKGROUND: We have previously reported that interleukin-10 (IL-10) deficient dendritic cells (DCs) are potent antigen presenting cells that induced elevated protective immunity against Chlamydia. To further investigate the molecular and biochemical mechanism underlying the superior immunostimulatory property of IL-10 deficient DCs we performed proteomic analysis on protein profiles from Chlamydia-pulsed wild-type (WT) and IL-10-/- DCs to identify differentially expressed proteins with immunomodulatory properties. RESULTS: The results showed that alpha enolase (ENO1), a metabolic enzyme involved in the last step of glycolysis was significantly upregulated in Chlamydia-pulsed IL-10-/- DCs compared to WT DCs. We further studied the immunoregulatory role of ENO1 in DC function by generating ENO1 knockdown DCs, using lentiviral siRNA technology. We analyzed the effect of the ENO1 knockdown on DC functions after pulsing with Chlamydia. Pyruvate assay, transmission electron microscopy, flow cytometry, confocal microscopy, cytokine, T-cell activation and adoptive transfer assays were also used to study DC function. The results showed that ENO1 knockdown DCs had impaired maturation and activation, with significant decrease in intracellular pyruvate concentration as compared with the Chlamydia-pulsed WT DCs. Adoptive transfer of Chlamydia-pulsed ENO1 knockdown DCs were poorly immunogenic in vitro and in vivo, especially the ability to induce protective immunity against genital chlamydia infection. The marked remodeling of the mitochondrial morphology of Chlamydia-pulsed ENO1 knockdown DCs compared to the Chlamydia-pulsed WT DCs was associated with the dysregulation of translocase of the outer membrane (TOM) 20 and adenine nucleotide translocator (ANT) 1/2/3/4 that regulate mitochondrial permeability. The results suggest that an enhanced glycolysis is required for efficient antigen processing and presentation by DCs to induce a robust immune response. CONCLUSIONS: The upregulation of ENO1 contributes to the superior immunostimulatory function of IL-10 deficient DCs. Our studies indicated that ENO1 deficiency causes the reduced production of pyruvate, which then contributes to a dysfunction in mitochondrial homeostasis that may affect DC survival, maturation and antigen presenting properties. Modulation of ENO1 thus provides a potentially effective strategy to boost DC function and promote immunity against infectious and non-infectious diseases. |
Evaluation of TaqMan Array Card (TAC) for the Detection of Central Nervous System Infections in Kenya.
Onyango CO , Loparev V , Lidechi S , Bhullar V , Schmid DS , Radford K , Lo MK , Rota P , Johnson BW , Munoz J , Oneko M , Burton D , Black CM , Neatherlin J , Montgomery JM , Fields B . J Clin Microbiol 2017 55 (7) 2035-2044 ![]() Infections of the central nervous system (CNS) are often acute with significant morbidity and mortality. Routine diagnosis of such infections is limited in developing countries and requires modern equipment in advanced laboratories that may be unavailable to a number of patients in sub-Saharan Africa. We developed a TaqMan Array Card (TAC) that detects multiple pathogens simultaneously from cerebrospinal fluid (CSF). The 21-pathogen TAC assays include two parasites (Balamuthia mandrillaris and Acanthamoeba), six bacterial pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Mycoplasma pneumoniae, Mycobacterium tuberculosis, and Bartonella) and 13 viruses (parechovirus, dengue, nipah, varicella zoster, mumps, measles, lyssa, herpes simplex virus 1 and 2, Epstein Barr virus, enterovirus, cytomegalovirus and chikungunya). The card also includes human RNAse P as a nucleic acid extraction control and an internal manufacturer control (glyceraldehyde 3-phosphate dehydrogenase (GAPDH)). This CNS-TAC can test up to eight samples for all 21 agents within 2.5 hours following nucleic acid extraction. The assay was validated for linearity, limit of detection, sensitivity and specificity by either using live viruses (dengue, mumps and measles) or nucleic acid material (nipah and chikungunya). Of the 120 samples tested by individual real-time PCR (IRTP), 35 were positive for eight different targets while CNS-TAC detected 37 positive samples across nine different targets. The TAC assays showed 85.6% sensitivity and 96.7% specificity across the assays. This assay may be useful for outbreak investigation and surveillance of suspected neurological disease. |
Role of Epithelial-Mesenchyme Transition in Chlamydia Pathogenesis.
Igietseme JU , Omosun Y , Stuchlik O , Reed MS , Partin J , He Q , Joseph K , Ellerson D , Bollweg B , George Z , Eko FO , Bandea C , Liu H , Yang G , Shieh WJ , Pohl J , Karem K , Black CM . PLoS One 2015 10 (12) e0145198 ![]() Chlamydia trachomatis genital infection in women causes serious adverse reproductive complications, and is a strong co-factor for human papilloma virus (HPV)-associated cervical epithelial carcinoma. We tested the hypothesis that Chlamydia induces epithelial-mesenchyme transition (EMT) involving T cell-derived TNF-alpha signaling, caspase activation, cleavage inactivation of dicer and dysregulation of micro-RNA (miRNA) in the reproductive epithelium; the pathologic process of EMT causes fibrosis and fertility-related epithelial dysfunction, and also provides the co-factor function for HPV-related cervical epithelial carcinoma. Using a combination of microarrays, immunohistochemistry and proteomics, we showed that chlamydia altered the expression of crucial miRNAs that control EMT, fibrosis and tumorigenesis; specifically, miR-15a, miR-29b, miR-382 and MiR-429 that maintain epithelial integrity were down-regulated, while miR-9, mi-R-19a, miR-22 and miR-205 that promote EMT, fibrosis and tumorigenesis were up-regulated. Chlamydia induced EMT in vitro and in vivo, marked by the suppression of normal epithelial cell markers especially E-cadherin but up-regulation of mesenchymal markers of pathological EMT, including T-cadherin, MMP9, and fibronectin. Also, Chlamydia upregulated pro-EMT regulators, including the zinc finger E-box binding homeobox protein, ZEB1, Snail1/2, and thrombospondin1 (Thbs1), but down-regulated anti-EMT and fertility promoting proteins (i.e., the major gap junction protein connexin 43 (Cx43), Mets1, Add1Scarb1 and MARCKSL1). T cell-derived TNF-alpha signaling was required for chlamydial-induced infertility and caspase inhibitors prevented both infertility and EMT. Thus, chlamydial-induced T cell-derived TNF-alpha activated caspases that inactivated dicer, causing alteration in the expression of reproductive epithelial miRNAs and induction of EMT. EMT causes epithelial malfunction, fibrosis, infertility, and the enhancement of tumorigenesis of HPV oncogene-transformed epithelial cells. These findings provide a novel understanding of the molecular pathogenesis of chlamydia-associated diseases, which may guide a rational prevention strategy. |
Serological measures of trachoma transmission intensity
Martin DL , Wiegand R , Goodhew B , Lammie P , Black CM , West S , Gaydos CA , Dize L , Mkocha H , Kasubi M , Gambhir M . Sci Rep 2015 5 18532 Ocular infection with Chlamydia trachomatis can lead to trachoma, a leading infectious cause of blindness. Trachoma is targeted for elimination by 2020. Clinical grading for ocular disease is currently used for evaluating trachoma elimination programs, but serological surveillance can be a sensitive measure of disease transmission and provide a more objective testing strategy than clinical grading. We calculated the basic reproduction number from serological data in settings with high, medium, and low disease transmission based on clinical disease. The data showed a striking relationship between age seroprevalence and clinical data, demonstrating the proof-of-principle that age seroprevalence predicts transmission rates and therefore could be used as an indicator of decreased transmission of ocular trachoma. |
Construction of Recombinant HVT Expressing PmpD, and Immunological Evaluation against Chlamydia psittaci and Marek's Disease Virus.
Liu S , Sun W , Chu J , Huang X , Wu Z , Yan M , Zhang Q , Zhao P , Igietseme JU , Black CM , He C , Li Y . PLoS One 2015 10 (4) e0124992 ![]() Chlamydia psittaci (C. psittaci) is an obligate intracellular zoonotic pathogen that can be transmitted to humans from birds. No efficacious commercial vaccine is available for clearing chlamydial infection due to lack of potential vaccine candidates and effective delivery vehicles. Herpesvirus of turkeys (HVT) is an efficacious commercially available vaccine against Marek's Disease virus (MDV). In this study, a recombinant HVT-delivered vaccine against C. psittaci and Marek's disease was developed and examined. The 5'-terminus of pmpD gene (pmpD-N) encoding the N-terminal fragment of polymorphic membrane protein D of C. psittaci was inserted into a nonessential region of HVT genome using reverse genetics based on an infectious bacterial artificial chromosome (BAC) clone of HVT. The recombinant virus (rHVT-pmpD-N) was recovered from primary chicken embryo fibroblast (CEF) cells by transfection of modified HVT BAC DNA containing the pmpD-N gene. The rHVT-pmpD-N construct was confirmed to express PmpD-N by immunoblot and immunofluorescence. The rHVT-pmpD-N was stable during 20 passages in vitro. The growth kinetics of rHVT-pmpD-N was comparable to that of parental HVT in vitro and in vivo. One-day-old SPF chickens inoculated subcutaneously with rHVT-pmpD-N displayed increased PmpD-specific antibody levels and a vigorous PmpD-specific lymphocyte proliferation response using HVT vector or CEF cells as control. Furthermore, the percentage of CD4+ cells was significantly elevated in rHVT-pmpD-N-immunized birds as compared to the parental HVT. All chickens vaccinated with rHVT-pmpD-N or parental HVT were protected completely against challenge with a very virulent strain of Marek's Disease virus (MDV) RB-1B. Post challenge with C. psittaci CB7 strain, a significant decrease in respiratory distress, lesions and Chlamydia load was found in the rHVT-pmpD-N-vaccinated group compared to the parental HVT. In conclusion, our study suggests that the rHVT-pmpD-N live vaccine may be viable as a candidate dual vaccine that provides protection against both very virulent MDV and C. psittaci. |
The use of biomarkers of semen exposure in sexual and reproductive health studies
Snead MC , Black CM , Kourtis AP . J Womens Health (Larchmt) 2014 23 (10) 787-91 ![]() Biomarkers of semen exposure have been used in studies investigating the safety and efficacy of barrier methods of contraception. They have been used as objective indicators of semen exposure when studying sexual behaviors and in human immunodeficiency virus/sexually transmitted infection research interventions where participants are advised to avoid unprotected sex. Semen biomarkers have also been used to assess or validate self-reported sexual behaviors or condom use in reproductive health settings. Prostate-specific antigen (PSA) and Y chromosome DNA (Yc-DNA) have each been evaluated in the past as semen biomarkers and are the most widely used in the field. While both are considered reliable for evaluating exposure to semen, each has unique characteristics. In this report, we summarize the literature and provide some considerations for reproductive health researchers who are interested in using PSA or Yc-DNA as semen biomarkers. We also synthesize our previous published work on the optimal conditions of collecting and storing specimens and assay performance in the presence of other vaginal products that may influence various assays. Semen biomarkers are innovative and promising tools to further study and better understand women's reproductive and sexual health and behavior. More research is needed to better understand the strengths, limitations, and optimal performance conditions of specific assays in vivo. |
Does tenofovir gel or do other microbicide products affect detection of biomarkers of semen exposure in vitro?
Snead MC , Kourtis AP , Melendez JH , Black CM , Mauck CK , Penman-Aguilar A , Chaney DM , Gallo MF , Jamieson DJ , Macaluso M , Doncel GF . Contraception 2014 90 (2) 136-41 OBJECTIVES: There is currently no information on whether products evaluated in HIV microbicide trials affect the detection of the semen biomarkers prostate-specific antigen (PSA) or Y chromosome DNA. STUDY DESIGN: We tested (in vitro) dilutions of tenofovir (TFV), UC781 and the hydroxyethylcellulose (HEC) placebo gels using the Abacus ABAcard and the quantitative (Abbott Architect total PSA) assays for PSA and Y chromosome DNA by real-time polymerase chain reaction. RESULTS: TFV gel and the HEC placebo adversely affected PSA detection using the ABAcard but not the Abbott Architect total PSA assay. UC781 adversely affected both the ABAcard and Abbott Architect total PSA assays. While there were some quantitative changes in the magnitude of the signal, none of the products affected positivity of the Y chromosome assay. CONCLUSIONS: The presence of TFV or HEC gels did not affect quantitative PSA or Y chromosome detection in vitro. Confirmation of these findings is recommended using specimens obtained following use of these gels in vivo. IMPLICATIONS: Researchers should consider the potential for specific microbicides or any products to affect the particular assay used for semen biomarker detection. The ABAcard assay for PSA detection should not be used with TFV UC781, or HEC. |
Detection of two biological markers of intercourse: prostate-specific antigen and Y-chromosomal DNA
Jamshidi R , Penman-Aguilar A , Wiener J , Gallo MF , Zenilman JM , Melendez JH , Snead M , Black CM , Jamieson DJ , Macaluso M . Contraception 2013 88 (6) 749-57 BACKGROUND: Although biological markers of women's exposure to semen from vaginal intercourse have been developed as surrogates for risk of infection or probability of pregnancy, data on their persistence time and clearance are limited. STUDY DESIGN: During 2006-2008, 52 couples were enrolled for three 14-day cycles of abstinence from vaginal sex during which women were exposed in the clinic to a specific quantity (10, 100 or 1000 muL) of their partner's semen. Vaginal swabs were collected before and at 1, 6, 12, 24, 48, 72 and 144 h after exposure for testing for prostate-specific antigen (PSA) and Y-chromosome DNA (Yc DNA). RESULTS: Immediately after exposure to 1000 muL of semen, the predicted sensitivity of being PSA positive was 0.96; this decreased to 0.65, 0.44, 0.21 and 0.07 at 6, 12, 24 and 48 h, respectively. Corresponding predicted sensitivity of being Yc DNA positive was 0.72 immediately postexposure; this increased to 0.76 at 1 h postexposure and then decreased to 0.60 (at 6 h), 0.63 (at 12 h), 0.49 (at 24 h), 0.21 (at 48 h), 0.17 (at 72 h) and 0.12 (at 144 h). CONCLUSIONS: Overall findings suggest that PSA may be more consistent as a marker of very recent exposure and that Yc DNA is more likely to be detected in the vagina after 12 h postexposure compared to PSA. |
Reply to shao et Al
Igietseme JU , Black CM . J Infect Dis 2013 208 (4) 709-10 We thank Shao et al for their correspondence [1], in which they recognized the potential significance of our recent article [2]. We also appreciate the constructive and fair criticism they raised. In particular, Shao et al felt that additional experiments are needed to strengthen the findings and conclusions. We would like to issue the following clarifications. | First, it is pertinent to clarify that Chlamydia-induced, caspase-mediated apoptosis alone was not the major driver for our study; perhaps more centrally significant to the infertility model investigated is Dicer, the fertility-promoting, microRNA (miRNA)–processing RNAse III enzyme that is a target for key caspases induced by chlamydial infection. Of course, the miRNA alteration, which may be a sequel to Dicer perturbation, would have a major effect in the regulation of biological processes associated with reproductive fertility in particular and development in general. We agree with Shao et al that HeLa cell lines may be different than oviduct epithelial cells with respect to the kinetics and time course of apoptosis. In fact, although we have used HeLa cells to demonstrate caspase-mediated apoptosis in this study (since they are reproductive tract epithelial cells commonly used to propagate chlamydiae in vitro), our future studies will likely use oviduct-derived epithelial cells to further investigate the molecular aspects of miRNA alteration concomitant with caspase cleavage inactivation of Dicer. In addition, we agree that studies of Chlamydia-infected human oviducts would better define the key cellular and molecular events that accompany the progression of the pathologic processes leading to infertility; however, such studies would require normal human specimens. |
Development of PCR assays for detection of Trichomonas vaginalis in urine specimens.
Bandea CI , Joseph K , Secor EW , Jones LA , Igietseme JU , Sautter RL , Hammerschlag MR , Fajman NN , Girardet RG , Black CM . J Clin Microbiol 2013 51 (4) 1298-300 ![]() Trichomonas vaginalis infections are usually asymptomatic or can result in non-specific clinical symptoms, which makes laboratory-based detection of this protozoan parasite essential for diagnosis and treatment. We report the development of a battery of highly sensitive and specific PCR assays for detection of T. vaginalis in urine, a non-invasive specimen, and development of a protocol for differentiating among Trichomonas species that commonly infect humans. |
Prevention of Chlamydia-induced infertility by inhibition of local caspase activity
Igietseme JU , Omosun Y , Partin J , Goldstein J , He Q , Joseph K , Ellerson D , Ansari U , Eko FO , Bandea C , Zhong G , Black CM . J Infect Dis 2013 207 (7) 1095-104 Tubal factor infertility (TFI) represents 36% of female infertility and genital infection by Chlamydia trachomatis (Ct) as a major cause. While TFI is associated with host inflammatory responses to bacterial components, the molecular pathogenesis of Chlamydia-induced infertility remains poorly understood. We investigated the hypothesis that activation of specific cysteine proteases, the caspases, during Ct genital infection causes the disruption of key fertility-promoting molecules required for embryo development and implantation. We analyzed the effect of caspase inhibition on infertility and the integrity of Dicer, a caspase-sensitive, fertility-promoting ribonuclease III enzyme, and key micro-RNAs in the reproductive system. Genital infection with the inflammation- and caspase-inducing, wild-type Ct serovar L2 led to infertility, but the non-inflammation-inducing, plasmid-free strain did not. We confirmed that caspase-mediated apoptotic tissue destruction may contribute to chlamydial pathogenesis. Caspase-1 or -3-deficiency, or local administration of the pan caspase inhibitor, Z-VAD-FMK into normal mice protected against Chlamydia-induced infertility. Finally, the oviducts of infected infertile mice showed evidence of caspase-mediated cleavage inactivation of Dicer and alteration in critical miRNAs that regulate growth, differentiation and development, including mir-21. These results provide new insight into the molecular pathogenesis of TFI with significant implications for new strategies for treatment and prevention of chlamydial complications. |
Effect of topical vaginal products on the detection of prostate-specific antigen, a biomarker of semen exposure, using ABAcards
Snead MC , Kourtis AP , Black CM , Mauck CK , Brown TM , Penman-Aguilar A , Melendez JH , Gallo MF , Jamieson DJ , Macaluso M . Contraception 2012 88 (3) 382-6 BACKGROUND: Prostate-specific antigen (PSA) is a biomarker of recent semen exposure. There is currently only limited information on whether topical vaginal products affect PSA assays. We investigated this question using various dilutions of several vaginal products (lubricants and spermicides) and the Abacus ABAcard for PSA detection. STUDY DESIGN: Pooled semen controls and various dilutions of nonoxynol-9 (N9), carboxymethyl cellulose (CMC), Replens, Gynol 2, K-Y jelly, Astroglide, Surgilube, combined with pooled semen dilutions, were tested for PSA using the Abacus ABAcard. RESULTS: N9 (2% with saline) and CMC did not appear to affect the results of testing with the ABAcard, but not all semen dilutions were tested. The other products (including Replens and Gynol, which is 2% N9 with propylene glycol, K-Y, Astroglide and Surgilube) at some of the dilutions tested either affected or gave invalid results with PSA testing using the ABAcard. Both Gynol 2 and K-Y at 1:10 dilution gave false-positive results. CONCLUSIONS: Some vaginal products affect PSA results obtained by using the semiquantitative ABAcard. In vivo confirmation is necessary to further optimize PSA detection when topical vaginal products are present. |
Chlamydial infection in vitamin D receptor knockout mice is more intense and prolonged than in wild-type mice
He Q , Ananaba GA , Patrickson J , Pitts S , Yi Y , Yan F , Eko FO , Lyn D , Black CM , Igietseme JU , Thierry-Palmer M . J Steroid Biochem Mol Biol 2012 135 7-14 ![]() Vitamin D hormone (1,25-dihydroxyvitamin D) is involved in innate immunity and induces host defense peptides in epithelial cells, suggesting its involvement in mucosal defense against infections. Chlamydia trachomatis is a major cause of bacterial sexually transmitted disease worldwide. We tested the hypothesis that the vitamin D endocrine system would attenuate chlamydial infection. Vitamin D receptor knock-out mice (VDR(-/-)) and wild-type mice (VDR(+/+)) were infected with 10(3) inclusion forming units of Chlamydia muridarum and cervical epithelial cells (HeLa cells) were infected with C. muridarum at multiplicity of infection 5:1 in the presence and absence of 1,25-dihydroxyvitamin D(3). VDR(-/-) mice exhibited significantly higher bacterial loading than wild-type VDR(+/+) mice (P < 0.01) and cleared the chlamydial infection in 39 days, compared with 18 days for VDR(+/+) mice. Monocytes and neutrophils were more numerous in the uterus and oviduct of VDR(-/-) mice than in VDR(+/+) mice (P < 0.05) at d 45 after infection. Pre-treatment of HeLa cells with 10 or 100nM 1,25-dihydroxyvitamin D(3) decreased the infectivity of C. muridarum (P < 0.001). Several differentially expressed protein spots were detected by proteomic analysis of chlamydial-infected HeLa cells pre-treated with 1,25-dihydroxyvitamin D(3). Leukocyte elastase inhibitor (LEI), an anti-inflammatory protein, was up-regulated. Expression of LEI in the ovary and oviduct of infected VDR(+/+) mice was greater than that of infected VDR(-/-) mice. We conclude that the vitamin D endocrine system reduces the risk for prolonged chlamydial infections through regulation of several proteins and that LEI is involved in its anti-inflammatory activity. |
Optimal methods for collecting and storing vaginal specimens for prostate-specific antigen testing in research studies
Gallo MF , Snead MC , Black CM , Brown TM , Kourtis AP , Jamieson DJ , Carter M , Penman-Aguilar A , Macaluso M . Contraception 2012 87 (6) 830-5 BACKGROUND: Prostate-specific antigen (PSA) detected in vaginal fluid can be used in studies of HIV/sexually transmitted infection (STI) and pregnancy prevention as an alternative to relying on participant reports of exposure to semen. Optimal methods for collecting and storing specimens for this testing have not been determined. STUDY DESIGN: We conducted a controlled, in vitro experiment of 550 specimens spiked with semen to determine the effects of swab type (five types), storage conditions of the swabs (room temperature with or without desiccant or at -80 degrees C without desiccant) and time from collection to testing (seven intervals over the course of 12 months) on the identification of PSA. We performed factorial analysis of variance to identify factors influencing PSA detection. RESULTS: Concentrations of PSA detected in the swabs declined with time of storage over the 1-year experiment (p<.01). The 1-mL, rayon-tipped swab stored immediately at -80 degrees C following collection performed best. CONCLUSIONS: If immediate testing or freezer storage is not feasible, investigators should use a swab with 1-mL capacity with processing and testing as soon as possible after specimen collection. |
Chlamydia vaccines: recent developments and the role of adjuvants in future formulations
Igietseme JU , Eko FO , Black CM . Expert Rev Vaccines 2011 10 (11) 1585-96 Bacteria of the genus Chlamydia cause a plethora of ocular, genital and respiratory diseases that continue to pose a considerable public health challenge worldwide. The major diseases are conjunctivitis and blinding trachoma, non-gonococcal urethritis, cervicitis, pelvic inflammatory disease, ectopic pregnancy, tubal factor infertility and interstitial pneumonia. The rampart asymptomatic infections prevent timely and effective antibiotic treatments, and quite often clinical presentation of sequelae is the first evidence of an infection. Besides, significant broad coverage in population screening and treatment is economically and logistically impractical, and mass education for public awareness has been ineffective. The current medical opinion is that an efficacious prophylactic vaccine is the best approach to protect humans from chlamydial infections. Unfortunately, a human vaccine has yet to be realized despite successful veterinary vaccines. Fortunately, recent advances in chlamydial immunobiology, cell biology, molecular pathogenesis, genomics, antigen discovery and animal models of infections are hastening progress toward an efficacious vaccine. Thus, it is established that Chlamydia immunity is mediated by T cells and a complementary antibody response, and several potential vaccine candidates have been identified. However, further advances are needed in effective vaccine delivery systems and safe potent adjuvants to boost and sustain immune responses for long-lasting protective immunity. This article focuses on the current status of human chlamydial vaccine research, specifically how application of new delivery systems and human compatible adjuvants could lead to a timely achievement of efficacious Chlamydia vaccines. The ranking of the candidate vaccine antigens for human vaccine development will await the availability of results from studies in which the antigens are tested by comparable experimental standards, such as antigen-adjuvant combination, route of delivery and possible toxicity. |
Anogenital human papillomavirus in sexually abused and nonabused children: a multicenter study
Unger ER , Fajman NN , Maloney EM , Onyekwuluje J , Swan DC , Howard L , Beck-Sague CM , Sawyer MK , Girardet RG , Sautter RL , Hammerschlag MR , Black CM . Pediatrics 2011 128 (3) e658-65 OBJECTIVES: To characterize the epidemiology of genital human papillomavirus (HPV) infection in children without previous consensual sexual activity, comparing HPV prevalence by certainty of child sexual abuse (CSA). PATIENTS AND METHODS: Patients presenting for evaluation of CSA in 8 sites in Atlanta, Houston, Harrisburg, and New York City were recruited along with patients presenting for unrelated health visits. CSA certainty was classified as definite, probable, possible, or no evidence following published guidelines and the results of history, physical examination, and laboratory tests. Urine and swabs of external genitalia were tested for HPV using L1 consensus polymerase chain reaction. RESULTS: The study included 576 participants (89.9% female) aged 6 months to 13 years (mean: 7.9); 534 of whom were evaluated for CSA and 42 for unrelated reasons. Of those evaluated for CSA, 14 had genital warts. One or more HPV types were detected in 11.8% (61 of 517) of participants with adequate samples. HPV detection was more likely among abused participants (definite, probable, or possible) than among participants without evidence of CSA (13.7% and 1.3%, respectively; P < .0001) and increased with certainty of abuse (8.4%, 15.6%, and 14.5% in participants with possible, probable, and definite CSA, respectively; P < .0001). Participants aged 10 years or older had a higher prevalence of HPV (20.6%) than others (5.6%) (P < .0001). CSA, anogenital warts, and age were independently associated with HPV detection. CONCLUSIONS: HPV detection was associated with CSA and increased with CSA certainty. In this population, genital HPV seemed to behave as a sexually transmitted infection. |
Distribution of Chlamydia trachomatis genovars among youths and adults in Brazil
Machado AC , Bandea CI , Alves MF , Joseph K , Igietseme J , Miranda AE , Guimaraes EM , Turchi MD , Black CM . J Med Microbiol 2011 60 472-6 Despite a high prevalence of sexually transmitted Chlamydia trachomatis infections in Brazil and other countries in South America, very little is known about the distribution of C. trachomatis genovars. In this study, we genotyped C. trachomatis strains from urine or endocervical specimens collected from 163 C. trachomatis-positive female and male youths, and female adults, residing in two different regions of Brazil, the city of Goiania located in the central part of Brazil, and the city of Vitoria in the south-east region. C. trachomatis strains were genotyped by amplifying and sequencing the ompA gene encoding the chlamydial major outer-membrane protein, which is genovar specific. We found nine different C. trachomatis genovars: E (39.3 %), F (16.6 %), D (15.9 %), I (8.6 %), J (7.4 %), G (4.9 %), K (3.1 %), H (2.4 %) and B (1.8 %). The distribution of the C. trachomatis genovars in the two regions of Brazil was similar, and there was no statistically significant association of serovars with age, gender, number of sexual partners or clinical symptoms. The overall distribution of C. trachomatis genovars in Brazil appears similar to that found in other regions of the world, where E, D and F are the most common. This supports the notion that, during the last few decades, the overall distribution of C. trachomatis genovars throughout the world has been relatively stable. |
Induction of immune memory by a multisubunit chlamydial vaccine
Eko FO , Ekong E , He Q , Black CM , Igietseme JU . Vaccine 2011 29 (7) 1472-80 We tested the hypothesis that intramuscular immunization with a multisubunit chlamydial vaccine candidate will induce long lasting immune responses in mice. Accordingly, groups of female C57BL/6 mice were immunized intramuscularly with Vibrio cholerae ghosts (VCG) expressing the Poring B and polymorphic membrane protein-D proteins of Chlamydia trachomatis or a control antigen. Humoral and cell-mediated immune responses were evaluated following immunization and after live chlamydial infection. Immunization induced an anamnestic response characterized by chlamydial-specific IgG2a and IgA antibodies in sera and vaginal lavage as well as specific genital and splenic T cell responses. The results also revealed that the local mucosal and systemic cellular and humoral immune effectors induced in mice following immunization with the vaccine candidate are long lasting. Vaccinated mice cleared intravaginal challenge with 10(5) chlamydial inclusion forming units within 12 days compared to control mice, which shed up to 2x10(3)IFUs at this time point. Moreover, rechallenge of mice 98 days after resolution of the primary infection resulted in the recall and retention of a relatively high frequency of chlamydial-specific Th1 cells and IgG2a in the genital mucosa. These results provide the first evidence that a VCG-based multisubunit chlamydial vaccine is capable of effectively stimulating anamnestic systemic and mucosal immune responses in mice. The data support further vaccine evaluation and testing for induction of long-term protective immunity. |
Identification of candidate genes using the murine model of female genital tract infection with Chlamydia trachomatis
Lyons JM , Igietseme JU , Black CM , Morre SA . Drugs Today (Barc) 2009 45 Suppl B 51-9 ![]() The integrated approach to the study of female genital tract infection (GTI) with Chlamydia trachomatis is a conceptual framework through which a consistent and comprehensive evidence-based understanding of C. trachomatis GTI could evolve. One application of this approach has been to identify candidate genes that may play a role in the course and severity of C. trachomatis GTI in women, using human clinical and genetic data together with results obtained in the female mouse model to guide the selection process This model has been proven robust enough: i) to identify stable phenotypic differences in the course and outcome of GTI among commonly used immunocompetent inbred mouse stains that are used in the construction of gene knockout (KO) and transgenic mice; as well as ii) to serve as a platform in which to assess the influence of genetic differences among human genital tract isolates of C. trachomatis as well as between this biovar and the mouse biovar, Chlamydia muridarum. This review presents a summary of published and unpublished results from 25 years of studies in immunodeficient and gene-deficient KO mice that both inform our present understanding of the immunogenetics of C. trachomatis GTI and serve to guide candidate gene selection. |
Multicenter study of nucleic acid amplification tests for detection of chlamydia trachomatis and neisseria gonorrhoeae in children being evaluated for sexual abuse
Black CM , Driebe EM , Howard LA , Fajman NN , Sawyer MK , Girardet RG , Sautter RL , Greenwald E , Beck-Sague CM , Unger ER , Igietseme JU , Hammerschlag MR . Pediatr Infect Dis J 2009 28 (7) 608-13 ![]() BACKGROUND: Diagnosis of sexually transmitted infections in children suspected of sexual abuse is challenging due to the medico-legal implications of test results. Currently, the forensic standard for diagnosis of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections is culture. In adults, nucleic acid amplification tests (NAATs) are superior to culture for CT, but these tests have been insufficiently evaluated in pediatric populations for forensic purposes. METHODS: We evaluated the use of NAATs, using urine and genital swabs versus culture for diagnosis of CT and NG in children evaluated for sexual abuse in 4 US cities. Urine and a genital swab were collected for CT and NG NAATs along with routine cultures. NAAT positives were confirmed by PCR, using an alternate target. RESULTS: Prevalence of infection among 485 female children were 2.7% for CT and 3.3% for NG by NAAT. The sensitivity of urine NAATs for CT and NG relative to vaginal culture was 100%. Eight participants with CT-positive and 4 with NG-positive NAATs had negative culture results (P = 0.018 for CT urine NAATs vs. culture). There were 24 of 485 (4.9%) female participants with a positive NAAT for CT or NG or both versus 16 of 485 (3.3%) with a positive culture for either, resulting in a 33% increase in children with a positive diagnosis. CONCLUSIONS: These results suggest that NAATs on urine, with confirmation, are adequate for use as a new forensic standard for diagnosis of CT and NG in children suspected of sexual abuse. Urine NAATs offer a clear advantage over culture in sensitivity and are less invasive than swabs, reducing patient trauma and discomfort. |
Role of T lymphocytes in the pathogenesis of chlamydia disease
Igietseme JU , He Q , Joseph K , Eko FO , Lyn D , Ananaba G , Campbell A , Bandea C , Black CM . J Infect Dis 2009 200 (6) 926-34 Vaccines are needed to prevent the oculogenital diseases of Chlamydia trachomatis. Infected hosts develop immunity, although temporary, and experimental vaccines have yielded significant protective immunity in animal models, fueling the impetus for a vaccine. Because infections cause sequelae, the functional relationship between infection- and vaccine-induced immunity is unclear. We hypothesized that infection- and vaccine-induced immunity are functionally distinct, particularly in the ability to prevent sequelae. Chlamydia-immune mice, with immunity generated by either a previous infection or vaccination, exhibited a significant degree of protective immunity, marked by a lower-intensity, abbreviated course of infection. However, vaccinated mice were protected from infertility, whereas preinfected mice were not. Thus, infection-induced immunity does not prevent the pathologic process leading to infertility. Furthermore, T cell subsets, especially CD8 T cells, play a major role in Chlamydia-induced infertility. The results have important implications for the immunopathogenesis of chlamydial disease and new vaccine strategies. |
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