A Role for Interleukin-6 in Host Defense against Murine Chlamydia trachomatis Infection

Interleukin-6-deficient (IL-6(−/−)) knockout mice had significantly increased Chlamydia trachomatis levels in lung tissue and increased mortality compared to B6129F(2)/J controls early after intranasal infection. Gamma interferon production and chlamydia-specific antibody levels were consistent with a decreased but reversible Th1-like response in IL-6(−/−) mice. IL-6 is needed for an optimal early host response to this infection.