IFNG and chlamydia infectious disease: The role of IFN-γ in clearance and protection against chlamydia infection is supported by evidence from both human and animal studies.54-57 Despite the vigorous antibody response to chlamydia infection or in vaccine models across different mammalian species, the role of antibodies is still poorly understood with some studies reporting protection and others a disease-enhancing effect.58-60 This is not surprising due to the huge heterogeneity of the antibody responses and our incomplete understanding of this critical component of the immune system.