Abnormal response to glutamate of T lymphocytes from multiple sclerosis patients

Multiple sclerosis (MS) is an immune-mediate, inflammatory and demyelinating disease of the central nervous system (CNS). Since glutamate (Glu) is a modulator of T lymphocyte function and Glu excitotoxicity has been proposed as one of the mechanisms of the demyelination, we studied the responses of T lymphocytes from normal controls (NC), MS or other non-inflammatory neurological disease (ONND) patients to Glu, by measuring phytohemagglutinin-induced intracellular Ca²⁺ ([Ca²⁺]_i) rise (Fura-2 method) and cell proliferation (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay). No differences in the Glu (1 μM)-induced potentiation of the [Ca²⁺]_i rise were measured in T lymphocytes from all groups of subjects, while a significant decrease in the Glu (1 mM)-induced inhibition of cell proliferation was observed in T lymphocytes from MS patients. These data demonstrate that MS T lymphocytes abnormally respond to Glu.