title: Heterologous protection against rotavirus-induced disease in gnotobiotic piglets.
abstract: Administration per os of 2 X 10(6) fluorescent cell-forming units of a human serotype 3 rotavirus (RV-3) protected all of nine gnotobiotic piglets against severe diarrheal disease when they were challenged 10 to 14 days later with 8 X 10(3) fluorescent cell-forming units of virulent wild-type porcine rotavirus (AT/76). The porcine virus was similar antigenically to porcine prototype strain OSU, previously described as antigenically distinct from all four recognized human serotypes. Administration of RV-3 was associated with the development of serum-neutralizing antibody to both RV-3 and AT/76 in piglets that excreted RV-3. Neutralizing antibody levels to RV-3 and AT/76 increased rapidly postchallenge. Vaccinated piglets were not immune to infection with AT/76 but showed no or minimal gastrointestinal symptoms after challenge. Control nonvaccinated piglets that were fed AT/76 developed severe dehydrating diarrhea and low levels of neutralizing antibody to AT/76 alone. The apparent heterologous clinical protection observed in this study could have been predicted from results of in vitro assays. Neutralization tests with reduction of fluorescence focus indicated a one-way cross-reaction between RV-3 and AT/76 such that hyperimmune antiserum to RV-3 neutralized porcine virus to moderate titer, but not vice versa. The results emphasize the importance of neutralizing antibody in protection against disease and the need to determine reciprocal cross-neutralization titers, rather than serotype alone, in order to predict the ability of rotavirus strains to cross protect.
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis* / Q000276:immunology; D003429:Cross Reactions; D003967:Diarrhea / Q000517:prevention & control*; D004591:Electrophoresis, Polyacrylamide Gel; D005856:Germ-Free Life; D006801:Humans; D007231:Infant, Newborn; D009500:Neutralization Tests; D012367:RNA, Viral / Q000032:analysis; D011817:Rabbits; D012401:Rotavirus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D012400:Rotavirus Infections / Q000276:immunology* / Q000517:prevention & control; D012703:Serotyping; D013552:Swine
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral