INDUCTION OF T-CELL ADHESION BY ANTIGEN STIMULATION AND MODULATION BYTHE CORECEPTOR CD4

T cell adhesion induced after physiological stimulation by antigen was investigated using murine T cell hybridomas specific for a tetanus to xin peptide. By employing a novel assay, the T cell hybridomas were sh own to strongly adhere to peptide-pulsed APC in a dose-dependent fashi on. Adhesion peaked at 30-60 min and declined thereafter. This assay a llowed us to study the relationship between T cell adhesion and later activation responses using tetanus toxin peptide and alanine monosubst ituted analogs. We show that the degree of peptide-induced T cell adhe sion correlated with the magnitude of late functional responses. CD4, LPA-1 (CD11a/CD18), and CD28 were critical in the adhesion response. T he enhancing role of CD4 was further demonstrated by reduced levels of T cell adhesion and late responses of CD4(-) T cell hybridomas. Reexp ression of CD4 reversed these defects. Our data suggest a link between antigen-induced T cell adhesion and late responses and also suggest t hat signals mediated by TCR and CD4 coengagement may induce a greater activation and/or recruitment of molecules involved in T cell adhesion . (C) 1996 Academic Press, Inc.