Inhibition of mitogen induced blast transformation by a multiple sclerosis serum factor.

A factor in the sera of multiple sclerosis patients inhibits RNA, protein and DNA synthesis in actively metabolizing mitogen stimulated lymphocytes. Inhibition of macromolecular synthesis precedes cell death by 24 to 36 hours. The factor is effective on cells which are already committed to transformation by previous exposure to mitogen and cells which are simultaneously exposed to the factor and mitogen. Previous exposure of unstimulated cells to the factor does not alter their subsequent response to mitogen. The factor does not inhibit RNA synthesis of unstimulated lymphocytes isolated on a Ficoll-Hypaque gradient, nor is it toxic to these cells.