Characteristics of the cell-mediated immune response to rotavirus in suckling mice

The kinetics of rotavirus specific cell mediated immunity and rotavirus infection were compared in infected and uninfected inbred BALB-C mice. Lymphocytes transformation (LTF) in spleen cells exposed to varying doses of mouse rotavirus (MRV) and control antigens was carried out at intervals up to 60 days following infection. Rotavirus infection was monitored by the detection of rotavirus antigen in isolated small intestinal enterocytes using direct immunofluorescent assay. The severity of diarrhea was determined by the consistency of the feces and the amount of staining. The length of diarrhea was also recorded. Greater than 50% of enterocytes were positive for viral antigen by 24 hours. The number of positive cells decreased over the following 7 days and were negative after 8 days. Diarrhea began approximately 44 to 48 hours after inoculation and continued for about 5 to 6 days terminating within 24 hours of the end of the detection of viral antigen. Viral specific CMI activity appeared in the splenic lymphocytes as early as two days after infection and peaked around ten days post infection. This peak of activity closely followed the termination of diarrhea. The increase in specific CMI simultaneously with the cessation of virus replication suggests that cellular immunity may function as a limiting factor in disease.