THE IMMUNOGENICITY OF THE TYPE IV SECRETION SYSTEM IN ANAPLASMA MARGINALE By ERIC LYNN SUTTEN

by Eric L. Sutten, M.S. Washington State University August 2009 Chair: Wendy C. Brown Anaplasma marginale is an economically important tick-borne intraerythrocytic rickettsial pathogen of cattle that can cause fever, weight loss and death upon acute infection in naïve hosts. Immunization with isolated outer membrane (OM) fractions elicits protective immunity against infection, whereas immunization with individual proteins from the OM proteome fail to provide similar levels of protection. Studies have shown that type IV secretion system (T4SS) proteins of Anaplasma marginale elicit immune responses associated with protective immunity, which consist of IgG2 antibody production, CD4 T-cell stimulation, as well as interferon-γ secretion. The T4SS is a protein complex that is found in many gram-negative bacteria, and is used to actively transport effecteor molecules across the periplasmic space into the host cell. Therefore, initiating a protective response against this protein complex could produce a detrimental effect on bacterial survival and dissemination, making the T4SS a potentially good vaccine candidate. To enhance understanding of the possible relationships among proteins within the T4SS, monoclonal antibodies (mAb) were developed, and used to determine