title: Interactions between calf alveolar macrophages and parainfluenza-3 virus.
abstract: Cells washed from the lungs of freshly killed calves (lung wash cells; LWC) were cytotoxic for calf kidney (CK) target cells infected with parainfluenzavirus type 3 (Pi-3) when assayed by chromium release. LWC collected from 25 calves, including two gnotobiotic animals that had not previously been infected with Pi-3, were all cytotoxic, giving a specific chromium release between 11 and 50%. Cytotoxicity was detected at ratios of LWC to target cell as low as 5:1. The cytotoxic reaction required viable LWC, was inhibited by Pi-3 antiserum, and was not the result of virus-induced damage to the target cells. The cytotoxic cells in the LWC population were identified as alveolar macrophages from observations on glass adherence, phagocytic activity, killing by silica and fine-structural appearance. When LWC were added to CK cells or organ cultures of bovine trachea infected with Pi-3, the yield of virus was reduced for the first 2 to 3 days. However, subsequently, Pi-3 virus replicated in the LWC. Infection of LWC with Pi-3 virus reduced their cytotoxic activity. The significance of these interactions between alveolar macrophages and Pi-3 virus is discussed.
mesh_terms: D000818:Animals; D000914:Antibodies, Viral; D002417:Cattle; D002460:Cell Line; D003165:Complement System Proteins; D003601:Cytotoxicity Tests, Immunologic; D006358:Hot Temperature; D008264:Macrophages / Q000276:immunology*; D010224:Parainfluenza Virus 3, Human / Q000254:growth & development; D018108:Respirovirus
chemical_list: D000914:Antibodies, Viral; D003165:Complement System Proteins