Severe combined immunodeficiency (SCID) mice treated with neutralized anti-IFN-γ antibody, or RAG-1-/-/IFN-γR-/- mice exhibit increased susceptibility to C. trachomatis compared with RAG-1-/- mice, suggesting that IFN-γ exerts beneficial effects on host innate immunity for controlling Chlamydia infection (38). This evidence concerns the gene RAG1 and chlamydia infectious disease.