“…Although non-human primate SIV studies often used tetanus as a neo-antigen to evaluate the immune response after a primary immunization,28,37 pre-exposure to the tetanus antigen does not necessarily negate its utility in monitoring immunologic parameters in SIV-+ macaques. Considering the availability of other recall antigens, neo-antigens, mitogens, alloantigens and the continued development of other available immunological assays1,3,5,8,11,13,15,17,27,28,31,32,37, withholding the prophylactic vaccination of nonhuman primates is not warranted. TNPRC began vaccinating its animals in 2005.…”