Phenotypic markers and functional characteristics of T lymphocyte clones from cerebrospinal fluid in multiple sclerosis.

We have recently developed a technique for direct expansion of human T lymphocyte clones from cerebrospinal fluid (CSF) of patients with acute infections of the central nervous system (CNS). In the present study, T lymphocyte clones were established directly from the CSF of 4 patients with multiple sclerosis by limiting dilution in the presence of T cell growth factor and irradiated feeder cells. In 3 patients the CSF was obtained during an exacerbation of their disease. Cloning efficiencies ranged between 4 and 6%. About 40 clones per patient were available for surface marker analysis and functional studies. Typing of the clones for membrane antigens revealed the following results: 75-100% had the OKT4+8- and 0-25% the OKT4-8+ phenotype. Only one clone expressed both surface markers. When tested for PHA-dependent cytotoxicity, all OKT8+ clones and about 50% of the OKT4+ clones were found to express cytotoxic activity. Studies on the proliferative response showed that all OKT4+ and the majority of OKT8+ clones were capable of TCGF-independent, mitogen-induced proliferation. Screening of the clones for specific reactivity against a panel of antigens including measles virus, mumps virus, Epstein-Barr virus and myelin basic protein (MBP) did not reveal significant specific reactivity.