Parainfluenza-3 virus: difference in capacity of neuraminidase-weak and strong strains to infect young calves and to elicit cellular immune response.
Calves less than four weeks old could not be infected with a neuraminidase-weak strain of parainfluenza-3 virus (Pi3) but were successfully infected with either of two neuraminidase-strong strains. The criteria for infection were virus excretion, cell-mediated and antibody-mediated immune responses. In the lymphocyte stimulation test, calves infected with the neuraminidase-strong Pi3 strain Tüb-E6 responded more strongly to antigen prepared from this strain than to antigen from the heterologous Pi3 strain Um-23. The non-immunoglobulin haemagglutination inhibition activity of the liquid phase of nasal secretions of newborn calves decreased after treatment with Vibrio cholerae neuraminidase. For virus-bound neuraminidase the liquid phase from newborn calves was a richer substrate than the liquid phase from older animals.
D000818:Animals; D000831:Animals, Newborn; D000956:Antigens, Viral / Q000276:immunology; D002417:Cattle; D002418:Cattle Diseases / Q000209:etiology / Q000276:immunology*; D006385:Hemagglutination Inhibition Tests; D007111:Immunity, Cellular; D008214:Lymphocytes / Q000276:immunology; D009439:Neuraminidase / Q000378:metabolism*; D010224:Parainfluenza Virus 3, Human / Q000201:enzymology / Q000276:immunology / Q000472:pathogenicity*; D018184:Paramyxoviridae Infections / Q000209:etiology / Q000276:immunology / Q000662:veterinary; D018108:Respirovirus / Q000472:pathogenicity*
D000956:Antigens, Viral; D009439:Neuraminidase