The interaction of L-glutamic acid with human T lymphocytes

A specific interaction of [H-3]Glu with T lymphocytes from the blood of healthy donors (K-d = = 0.236 mu M) was revealed and described. It was found that unlabeled quisqualate, a structural analogue of L-glutamic acid, and unlabeled dipeptides Ala-Glu, Glu-Ala, and Glu-Glu competitively inhibit the specific binding of [H-3]Glu to T lymphocytes (with K-i 0.19, 2.4, 3.4, and 1.2 mu M, respectively). Binding experiments with conjugates of labeled and unlabeled glutamic acid with dextran showed that the receptors of [H-3]Glu are localized on the outer surface of the plasma membrane of T lymphocytes.