Studies on the immune response and pathogenesis of Sendai virus infection of mice. III. The effects of cyclophosphamide.

Studies of the effects of cyclophosphamide on a non-lethal primary Sendai virus infection of mice are reported. Treatment with cyclophosphamide resulted in failure to limit or eradicate virus, diminished and delayed the appearance of immunoglobulin-secreting cells in the lungs and the production of local and serum antibody, reduced and delayed the appearance of bronchial basement membrane damage and the desquamation of infected mucosal cells, and reduced the incidence of immune complex deposition in the kidneys. Evidence is presented which indicated that some escape from immunosuppression occured by day 6, resulting in local antibody production. The appearance of the local antibody response was associated with increased tissue damage in the lungs and the deposition of immune complexes of viral antigen and antibody in the kidney. Nine further experiments were performed in mice to investigate this renal manifestation and preliminary results are presented. In four of seven Sendai and one of two avirulent influenza A (Kunz) virus infections glomerular immune complexes were found. Studies in C3H and C57 B1 mice and their F1 hybrid suggested that genetic factors play some part in the renal findings. The results are discussed with respect to the possible beneficial and harmful effects of the immune response to trivial respiratory virus infections.