Role of natural killer cells in infection with the mouse pneumonitis agent (murine Chlamydia trachomatis).

Natural killer (NK) activity is increased in both spleen and lung early in pulmonary infection by murine Chlamydia trachomatis in both susceptible nude and resistant heterozygous (nu/+) mice. Ablation of the rise in NK activity by giving the mice antiasialo GM-1 antibody or stimulation of NK activity by immunomodulators did not affect quantitative tissue counts of the mouse pneumonitis biovar of C. trachomatis or significantly affect survival. Studies are needed to further define the role of NK cells in host defense, immunoregulation, and immunopathology during chlamydial infection.