Studies of pulmonary and renal immunopathology after nonlethal primary sendai viral infection in normal and cyclophosphamide-treated hamsters.

Hamsters were infected by aerosol with a nonlethal strain of Sendai virus. The virus infected mainly bronchial mucosal cells, some alveolar cells, and occasional renal tubular cells. By the third day after infection, there was an impressive local influx of inflammatory and IgG-secreting cells at sites of infection, disruption and desquamation of infected mucosal cells, and destruction of bronchial basement membrane. These findings were associated with the presence of specific antibodies bound to viral antigens in the tissues. Treatment with cyclophosphamide resulted in the ablation of these histologic events, failure to eradicate virus or to produce antibody, and some spontaneous deaths. Viral antigens were regularly detected in kidneys on days 3, 6, and 9 as a fine, granular glomerular and tubular basement membrane staining pattern after elution of tissue sections. The IgG deposition was found in a similar pattern at the same times, persisted after Sendai antigens could no longer be detected, and tended toward linear staining, fading with time. Treatment with cyclophosphamide decreased significantly, but did not completely abolish, the renal abnormalities. It was concluded that the humoral immune response is associated with eradication of virus, excess local tissue damage, and some immunopathologic consequences in the kidney.