Neutralization Test by New Isolates of Human Rotavirus

Thre newly isolated human rotaviruses in MA104 cells were used as antigens in the neutralization test of paired sera of infants and young children with acute gastroenteritis during three epidemic seasons. Twenty-three of 41 paired sera (56%) from outpatients with acute gastroenteritis responded with development of NT antibody to one, two, or three antigens. Of 23 paired sera which showed significant rises of antibody to any strain, 20 paired sera (87%) responded to strain Hochi, 15 cases (65%) to strain Ito, and 16 cases (70%) to strain Nemoto. Ten of 14 cases that were seronegative to any isolated strain at onset of illness showed significant rises of antibodies to three strains. Three strains were determined to be subgroup 2 by RNA pattern and were recently found to be similar if not identical to serotype 3 and 4 by Wyatt et al. The neutralization test showed extensive immunologic cross-reativity among these strains. The rate of acquisition of serum antibody by age was similar with the three antigens.