Taken together, the Montanide formulations that induced the best protection against abortion and reduced bacterial shedding also primed for chlamydial antigen-specific inflammatory cytokines (IFN-γ and IL-17A) but not regulatory (IL-4) or anti-inflammatory (IL-10) cytokines, fitting with the paradigm that vaccines capable of inducing Th-1 type responses are likely to be protective against chlamydial infections. This evidence concerns the gene IFNG and abortion.