Antibodies to myelin basic protein and measles virus in multiple sclerosis: precursor frequency analysis of the antibody producing B cells.

Antibody-producing B lymphocytes were polyclonally activated and transformed, by Epstein-Barr virus (EBV), into multiple B lymphoblastoid cell lines in a microculture system. The frequencies of B precursor cells producing antibodies to myelin basic protein (MBP) and measles virus were analyzed in peripheral blood of patients with multiple sclerosis (MS) and control subjects. Measles virus-specific B cells were detected at a significantly higher frequency in MS patients (n = 10, P less than 0.005) than patients with other neurological diseases (n = 10) and normal subjects (n = 10). In contrast, the frequencies of B cells producing anti-MBP antibodies and natural antibodies did not differ statistically among the three groups tested (P greater than 0.05). In addition, the anti-MBP antibodies produced by a panel of stable B cell lines obtained were found to react selectively with an epitope(s) within the C-terminal half fragment 90-171 of the human MBP molecule. In our experiments, no antibody cross-reactivity between MBP and measles virus could be detected in a total of 2760 B cell cultures.