Enhancement of antigen incorporation and infectivity of cell cultures by human rotavirus.

Infection of cell cultures with human rotavirus preparations was attempted and the effects of trypsin and low-speed centrifugation on antigen incorporation, as demonstrated by immunofluorescence and radioimmunoassay, were determined. In addition, the effect of viral aggregation on antigen incorporation was investigated by filtering viral preparations. Four strains of human rotavirus were employed, and the results were compared to those obtained with two tissue culture-adapted animal rotaviruses. Centrifugation and trypsin appeared to have little or no effect on infectivity of the tissue culture-adapted (simian rotavirus) or -adaptable (Nebraska calf diarrhea virus) strains, whereas centrifugation and viral aggregation appeared to be essential for the human viruses. In addition, trypsin enhanced antigen incorporation of the human strains to some extent. Infectivity for cell cultures and in vitro human rotavirus protein formation was demonstrated by [35S]methionine incorporation, and the specificity of this human viral protein was established by radio-immunoprecipitation.