Identification of T-cell epitopes in the murine host response to Ehrlichia Chaffeensis

Abstract

We examined the cell-mediated immune response against the obligate intracellular bacterium Ehrlichia chaffeensis after single or multiple experimental antigen exposures. We confirmed that CD4 knock-out mice had longer delays in clearance of bacteria from the site of injection compared to wild-type B6 mice. However, the absence of CD8+ T cells did not affect clearance. We found that there was effective mobilization of splenic effector memory cells after primary and secondary experimental challenges. We designed several IAb-binding peptides using established algorithms and tested them for their ability to stimulate T-cell proliferation. Several of the IAb-binding peptides were immunogenic. The most stimulatory epitope was conserved between p28-OMP 14 and p28-OMP 19. Several E. chaffeensis p28-OMP 14 and p28-OMP 19H-2Kb binding peptides including IGGHFHKV, IGNEFRDI, and EAHRYCAL were also identified as epitopes for H-2b-restricted CD19−CD8+ T cells.