Abstracts Health Sciences

Characterization of Mycoplasma Alligatoris Immunodominant Antigens

by Niora Fabian

Mycoplasma alligatoris is a bacterial pathogen that causes acute lethal multisystemic inflammatory disease in alligators. Previous Western blotting experiments revealed antibody response patterns of experimentally inoculated and naturally infected American alligators (Alligator mississippiensis). In all individuals surviving the acute infection, a significant immune response was observed for an antigen approximately 64 kDa in size as early as 6 wk post-inoculation (PI), increasing in intensity until euthanasia 16 wk PI. For some individuals, a second antigen approximately 50 kDa in size was immunoreactive. The importance of this distinct initial humoral response is unknown, as alligators surviving the natural infection developed immune responses to many other antigens several years later. The goal of this study was to identify and characterize the 64 kDa immunodominant antigen to better understand its potential role in host-pathogen interactions in M. alligatoris mycoplasmosis. Two-dimensional gel electrophoresis (2DGE) and affinity chromatography-based antigen isolation experiments were performed using M. alligatoris membrane proteins and total proteins. Following Western blot confirmation, LC/MS/MS peptide sequencing, and de novo peptide sequencing, protein matches were evaluated with statistical algorithm-based proteome analysis software. Top immunodominant antigen candidates were obtained from 2DGE samples. These candidates could be evaluated for immunodominant antigen expression in subsequent studies. Though the 64 kDa M. alligatoris antigen is still unknown, future work involving improved antigen enrichment and resolution as well as testing candidates for immunodominant antigen expression may confirm its identity. This work may explain relative virulence of M. alligatoris and provide insight on pathogenesis of other Mycoplasma species and related organisms.