Induction of class I and class II transplantation antigens in rat brain during fatal and non-fatal measles virus infection

Measles virus induced a marked increase in the expression of MHC-coded class I and class II antigens as detected by immunostaining during both fatal and non-fatal brain infections in rats. The distribution of these molecules in the brain was much more widespread than the occurence of viral antigen suggesting a soluble factor for their induction. In 14-day-old rats with a non-fatal infection there was a marked infiltration of T lymphocytes of ‘cytotoxic/suppressor’ phenotype in the brain parenchyma, whereas T ‘helper’ cell phenotypes mainly were located perivascularly. In brains from newborn rats with a fatal infection no or only few lymphocytes were detected.