Virus-specific cytotoxic T lymphocytes in multiple sclerosis: a normal mumps virus response adds support for a distinct impairment in the measles virus response

An impairment of the measles virus-specific cytotoxic T lymphocyte response in multiple sclerosis was previously reported. This response is predominantly mediated by HLA class II-restricted CD4⁺ cells. In the present report, virus-specific cytotoxic T lymphocyte responses in multiple sclerosis were further studied by examining the response to mump virus. No significant difference was detected in the generation of mumps virus-specific cytotoxic T lymphocyte responses between normal individuals and multiple sclerosis patients with impaired measles virus-specific cytotoxicity. A portion of the mumps virus-specific cytotoxic T lymphocyte response could be mediated by HLA class II-restricted CD4⁺ cells generated from both normal controls and MS patients. This CD4⁺ cell-mediated portion of the response was similar in both groups. These findings support the view that there is a distinct measles virus-specific impairment in cell-mediated cytotoxicity in multiple sclerosis.