cellular studies showed that all BLSOmp31 formulations stimulated a mixed TH1-TH2 response ,represented by IFN-y and IL-4,respectively. as previously reported, cells from rams immunized with BLSOmp31 in IFA produced IFN-y indicating that immunization chimeric protein induces a Th1 cellular response mediated by activation of macrophages, which are the major effectors mediating the killing of the bacterium.