More importantly, extensive immunological characterizations of chlamydial infection in animal models have demonstrated that chlamydial antigen-specific immune responses mediated by IFNg and dominated by Th1 T cells are essential for protection against chlamydial infection [6], [15], [16], Thus, it may be possible to induce protective immunity using the chlamydial antigens if prepared and delivered appropriately. Here, IFNG is linked to chlamydia trachomatis infectious disease.