Pneumonia due to Chlamydia trachomatis in the immunocompromised (nude) mouse.

Athymic nude mice (nu/nu) were significantly more susceptible to pneumonia due to the agent of mouse pneumonitis (MoPn), Chlamydia trachomatis, than their heterozygous (nu/+) littermates, as judged both by a greater mortality and a decreased ability to rid their lungs of the infection. Nu/nu mice did not produce significant antibody to the MoPn agent, whereas nu/+ mice did. Thymic transplantation rendered nu/nu mice significantly more resistant to the MoPn agent than nu/nu controls. Resistance to the MoPn agent and production of specific antibody to the MoPn agent were dependent on thymus-derived cells.