Antibody reactive immunomes of and are diverse and defined by conformational antigenic determinants.

For decades, the defined antibody reactive proteins of and were limited to a small group with linear antibody epitopes. Recently, our laboratory has utilized an immunomics-based approach to rapidly screen and identify undefined and antigenic proteins and antibody epitopes. In this study, we analyzed the remaining portion (~50%) of the and proteomes ( = 444 and 405 proteins, respectively), that were not examined in previous studies, to define the complete immunomes of these important pathogens. Almost half of the proteins screened (196/444) reacted with antibodies in convalescent HME patient sera, while only 43 proteins reacted with CME dog sera. New major immunoreactive proteins were identified in ( = 7) and ( = 1), increasing the total number of (n = 14) and proteins (n = 18) that exhibited antibody reactivity comparable to well-defined major antigenic proteins (TRP120 and TRP19). All of the but only some major immunoreactive proteins contained major conformation-dependent antibody epitopes. The immunoreactive proteins were generally small (< 250 amino acids; ~27kDa) and the proteins were slightly larger (> 320 amino acids; ~35 kDa). The majority of these new major immunoreactive proteins were predicted to be type I secreted effectors, some of which contained transmembrane domains. Characterization of the immunomes of and and understanding the host specific immune responses will facilitate identification of protective antigens and define the biophysical epitope characteristics vital to effective vaccine development for the ehrlichioses.