Use of polyclonal and monoclonal antibodies and analysis of viral RNA in the detection of unusual group A human rotaviruses.

Immuno-enzymatic assay employing monoclonal antibodies and viral RNA analysis by gel electrophoresis were used to classify human group A rotaviruses (HRV) into subgroups I and II. Of 249 fecal samples positive for group A rotaviruses, 29 (11%) belonged to subgroup I and 215 (85%) were identified as subgroup II. Two samples (Ro-302 and Ro-500) contained mixed infections of the two subgroups. Three isolates belonged to neither one of the two subgroups, but they did not yield enough viral RNA to allow their classification. One subgroup I isolate (Ro-1845) contained components typical of subgroup II viruses in that it was identical to serotype 3 and yielded RNA with fast-moving 10th and 11th segments. After growth in culture, the two mixed infections yielded subgroup II viruses, which were identified as serotype 1. The three unclassified isolates grew poorly in culture and could not be further analyzed. The subgroup I isolate (Ro-1845) grew well in culture and yielded virus similar to the original one.