GAMMA-INTERFERON LEVELS DURING CHLAMYDIA-TRACHOMATIS PNEUMONIA IN MICE

Host defense against murine Chlamydia trachomatis (mouse pneumonitis a gent [MoPn]) in a murine model was investigated. Gamma interferon (IFN -gamma) was produced in the lungs by both MoPn-susceptible nude athymi c (nu/nu) and MoPn-resistant heterozygous (nu/+) mice. In vivo depleti on of IFN-gamma in nu/nu mice led to exacerbation of infection. Fluore scence-activated cell sorter analysis disclosed induction of GL3 antib ody-positive cells (putatively gamma/delta+ T cells) in nu/nu mouse lu ng during infection with MoPn. Treatment of nu/nu mice in vivo with an tibody to NK cells (anti-asialo GM1 antibody) or to gamma/delta cells (UC7-13D5) did not significantly decrease IFN-gamma production in the lung. However, treatment of severe combined immunodeficiency mice (whi ch lack gamma/delta cells) with antibody to NK cells significantly red uced lung IFN-gamma levels.