Immunological aspects of interaction between rotavirus and the intestine in infancy.

Rotaviruses are important pathogens causing severe diarrhoea in human infants and young animals. Available information on the pathogenic mechanisms of and the immune response to rotaviruses is reviewed here. Studies in our laboratory using the suckling mouse model have focused on elucidating the nature of interaction between the virus and the gut, and on the importance of T and B cell mediated immunity in protection and recovery from the disease. Our data suggest that the age dependence of mouse rotavirus (MRV) infection is related to the presence of virus-specific receptors on the enterocytes. The uptake of rotavirus antigens appears to be limited to the epithelium associated with Peyer's patches. The antigen is transported to local and regional lymph nodes. Recent studies have indicated that rotavirus infection also increases the uptake of other macromolecules in the intestine. Rotavirus-specific mucosal IgA response seems to be related to the location and magnitude of MRV antigen in the lymph follicles in different segments of the small intestine. Studies in mice with different types of immunodeficiency suggest that a specific immune response is required for complete resolution of virus infection. Several parameters of immunity to rotavirus infection have been examined and, similar to other reports, local immunity in the intestine appears to have the most important role in protection. It also has been observed that nutritional factors may be important in modifying disease. However, there are still many questions to be answered concerning the role of immunity in mediating the pathogenesis of rotavirus infection.