TY - JOUR
T1 - CPAF selectively degrades chlamydial T cell antigens for inhibiting antigen presentation
AU - Zhang, Yuyang
AU - Zhong, Guangming
AU - Cai, Huihua
AU - Chen, Siping
AU - Sun, Donghua
AU - Zhang, Dongmei
AU - He, Yuanli
N1 - Publisher Copyright:
© 2017 Zhang et al.
PY - 2017/11
Y1 - 2017/11
N2 - Introduction: Chlamydia trachomatis is the leading cause of sexually transmitted bacterial disease, which may cause significant threats, such as pelvic inflammatory disease and tubal factor infertility, to women if untreated. The pathological mechanisms of chlamydia-induced disease remain largely unknown, but it has been proposed that CPAF, a chlamydia-secreted serine protease, may play major roles in aiding chlamydial infection and contribute to chlamydia pathogenesis during in vivo infection. According to previous results, CPAF targets host immunity by degrading antimicrobial peptides and neutralizing complement activity; however, whether CPAF is involved in chlamydial antigen presentation has never been reported. Methodology: Antigen presentation assay was used to monitor the effects of CPAF on OT1-, OT2-, and chlamydia T cell antigen-mediated antigen presentation. In vitro cell-free degradation assay was used to detect CPAF processing of chlamydia T cell antigens. Results: We found that CPAF preferably inhibits OT2- but not OT1-mediated antigen presentation. CPAF inhibits OT2 antigen presentation by direct proteolytic cleavage in the wild type CPAF, but not enzymatic mutants. Importantly, several previously identified chlamydial T cell antigens were selectively degraded by CPAF when co-incubated in vitro. In addition, specific inhibition T cell antigen presentation by CPAF was correlated with T cell antigen cleavage by CPAF in vitro assay. Conclusions: Our experiments demonstrated that CPAF selectively and specifically degrades chlamydial T cell antigens, which chlamydia may utilize as a novel mechanism for evading host immune responses to promote chlamydia survival.
AB - Introduction: Chlamydia trachomatis is the leading cause of sexually transmitted bacterial disease, which may cause significant threats, such as pelvic inflammatory disease and tubal factor infertility, to women if untreated. The pathological mechanisms of chlamydia-induced disease remain largely unknown, but it has been proposed that CPAF, a chlamydia-secreted serine protease, may play major roles in aiding chlamydial infection and contribute to chlamydia pathogenesis during in vivo infection. According to previous results, CPAF targets host immunity by degrading antimicrobial peptides and neutralizing complement activity; however, whether CPAF is involved in chlamydial antigen presentation has never been reported. Methodology: Antigen presentation assay was used to monitor the effects of CPAF on OT1-, OT2-, and chlamydia T cell antigen-mediated antigen presentation. In vitro cell-free degradation assay was used to detect CPAF processing of chlamydia T cell antigens. Results: We found that CPAF preferably inhibits OT2- but not OT1-mediated antigen presentation. CPAF inhibits OT2 antigen presentation by direct proteolytic cleavage in the wild type CPAF, but not enzymatic mutants. Importantly, several previously identified chlamydial T cell antigens were selectively degraded by CPAF when co-incubated in vitro. In addition, specific inhibition T cell antigen presentation by CPAF was correlated with T cell antigen cleavage by CPAF in vitro assay. Conclusions: Our experiments demonstrated that CPAF selectively and specifically degrades chlamydial T cell antigens, which chlamydia may utilize as a novel mechanism for evading host immune responses to promote chlamydia survival.
KW - Antigen presentation
KW - CPAF
KW - Chlamydia
KW - Host immunity
UR - http://www.scopus.com/inward/record.url?scp=85037729504&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85037729504&partnerID=8YFLogxK
U2 - 10.3855/jidc.9356
DO - 10.3855/jidc.9356
M3 - Article
C2 - 31618186
AN - SCOPUS:85037729504
SN - 2036-6590
VL - 11
SP - 868
EP - 875
JO - Journal of Infection in Developing Countries
JF - Journal of Infection in Developing Countries
IS - 11
ER -