CPAF selectively degrades chlamydial T cell antigens for inhibiting antigen presentation

  • Yuyang Zhang Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
  • Guangming Zhong University of Texas Health Science Center at San Antonio, San Antonio, United States
  • Huihua Cai Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
  • Siping Chen Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
  • Donghua Sun Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
  • Dongmei Zhang Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
  • Yuanli He Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
Keywords: Chlamydia, CPAF, antigen presentation, host immunity

Abstract

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.

Author Biographies

Yuyang Zhang, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China

Department of Obstetrics and Gynecology, Zhujiang Hospital

Guangming Zhong, University of Texas Health Science Center at San Antonio, San Antonio, United States

Department of Microbiology, Immunology & Molecular Genetics

Huihua Cai, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China

Department of Obstetrics and Gynecology, Zhujiang Hospital

Siping Chen, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China

Department of Obstetrics and Gynecology, Zhujiang Hospital

Donghua Sun, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China

Department of Obstetrics and Gynecology, Zhujiang Hospital

Dongmei Zhang, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China

Department of Obstetrics and Gynecology, Zhujiang Hospital

Yuanli He, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China

Department of Obstetrics and Gynecology, Zhujiang Hospital

Published
2017-12-10
How to Cite
1.
Zhang Y, Zhong G, Cai H, Chen S, Sun D, Zhang D, He Y (2017) CPAF selectively degrades chlamydial T cell antigens for inhibiting antigen presentation. J Infect Dev Ctries 11:868-875. doi: 10.3855/jidc.9356
Section
Original Articles