Rotavirus-specific T-cell responses in young prospectively followed-up children.

Rotavirus is a major cause of gastroenteritis in young children. Antibodies seem to protect against rotavirus infection but cell-mediated immune responses are probably also important for protection. We evaluated the development of T-cell responses to rotavirus in follow-up samples from 20 healthy children with an increased genetic risk for type 1 diabetes. Blood samples from 16 healthy adults were also available for the study. T-cell proliferation was analysed at 3-6 month intervals from the age of 3 months to the age of 4-5 years using the Wa strain of human rotavirus and the NCDV strain of bovine rotavirus as antigens. IgG and IgA antibodies to rotavirus were studied from simultaneously drawn plasma samples with EIA method using NCDV as an antigen. A total of 24 infections were revealed by antibody analysis. Sixteen children showed diagnostic increases in both IgG and IgA antibodies to rotavirus, while 5 children showed increases in IgA antibodies only and 3 in IgG only. Antibody rises were accompanied by T-cell responses to rotavirus (SI > 3) in 9 of the 24 cases. T-cell responses to purified or lysed human rotavirus were stronger after a rise in rotavirus antibodies than the responses before infection (P = 0.017 and 0.027, respectively). There was a correlation between T-cell responses to purified and lysed human rotavirus and NCDV. Strong T-cell responses to rotavirus were transient and the ability to respond usually disappeared in one year, but in all adults T-cell responses to rotavirus were strong implicating that several infections are needed to develop consistent, strong T-cell responsiveness.