Replication as a determinant of the intestinal response to rotavirus.

Mucosal antibody induction by otherwise identical replication-competent and replication-incompetent rhesus monkey rotaviruses was compared. Although psoralen-inactivated virus induced diarrhea, the magnitude of the intestinal antibody response was severely attenuated compared with that of replicating rotavirus, as determined by assay of mucosal antibody-secreting cells. Rotavirus that was neutralized by monoclonal antibodies (anti-VP4 and -VP7) prior to inoculation was similarly ineffective at induction of specific antibodies in intestinal secretions. In contrast to genetically inactivated virus, antibody-neutralized virus did not induce diarrhea. In this murine model, viral replication is an important determinant of antibody induction. The diarrhea response is blocked by neutralizing antibodies, but the mechanism of action is not exclusively the inhibition of viral replication.