Immunoproteomics of Relevant Chlamydial Antigens in Trachomatous Trichiasis Patients from Ethiopia and Sudan

Abstract

Purpose : Chlamydia trachomatis (Ct) is an obligate intracellular, Gram-negative bacterium capable of infecting and inducing inflammatory pathologies responsible for trachomatous trichiasis, corneal blindness, inflammatory damage in fallopian tubes and infertility.

Methods : Ct antigens relevant in trachoma were identified by quantitative immunoproteomics of proteins solubilized from elementary bodies (EBs) of Ct serovar B. Electrophoretically separated proteins of Ct EBs were probed with human sera obtained from 28 patients from trachoma endemic areas (Ehtiopia and Sudan) and data digitalized for statistical analysis after visualization of reactive bands. Prospective antigenic candidates of serovar B, as defined by the frequency and intensity of recognition, were further identified by nanoLC-high resolution mass spectrometry.

Results : Quantitative immunoproteomics analysis revealed relevant chlamydial antigens. Elongation factor-G, oligendopeptidase F, GroEL, type-III secretion system ATP-ase, major outer membrane protein, transaldolase, 30S ribosomal protein S5 and 50S ribosomal protein L19 could stand up as marker antigens of disease severity. The presence of several T3SS proteins late in the developmental cycle suggests a role in continuing the infectious process. Various T3SS proteins, identified in our study as prominent antigens and major protein hits identified by proteomics, could contribute to chlamydial invasion during entry or intracellular survival of the organism.

Conclusions : The present study identified trachoma relevant chlamydial antigens that could be useful for the development of more sensitive diagnostics and/or vaccine development against Ct.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.