Cell-mediated immunity in acute and chronic measles virus infections: 43

Abstract

While the etiology of subacute sclerosing panencephalitis (SSPE) by a measles-like virus is now firmly established, the pathogenesis of SSPE is not understood. It has been suggested that the disease might be due to a specific unresponsiveness at the level of T cells (Burnet, Lancet ii,610,1968). To test this hypothesis specific T cell functions were measured by direct lymphocyte-mediated cytotoxicity in vitro using measles virus-infected lymphoblasts as target cells in 4- hr Cr-51 release assays. Results: Cells with the properties of cytotoxic T lymphocytes (CTL) were only present in children with acute measles and could be found among peripheral blood lymphocytes for up to 7 days after onset of measles rash. These cells were functionally restricted by the HLA system and belonged to the FcRy negative pool of lymphocytes. Such cells could neither be detected in measles convalescents nor in patients with SSPE. It is proposed that in order to assess specific T cell immunity in donors beyond the acute stage of measles, memory T cells must first be restimulated in vitro into secondary populations of CTL before testing direct lymphocyte-mediated cytotoxicity.