title: The role of accessory cells in polyclonal T cell activation II. Induction of interleukin 2 responsiveness requires cell-cell contact.
abstract: It has previously been reported (Hünig, T. et al., Eur. J. Immunol. 1983. 13:1) that highly purified peripheral T cells do not respond to concanavalin A (Con A) even in the presence of Con A-induced spleen cell supernatant as a source of interleukin 2 (IL 2). In the present report, the hypothesis was tested whether this unresponsiveness correlates with the observed inability of Con A to mediate cell-cell contact between highly purified T cells. It was found that T cells, pretreated with neuraminidase to reduce their net negative charge, were both aggregated and rendered IL 2-reactive by Con A. In addition, leukoagglutinin (LA) was found to be able to both agglutinate untreated T cells and to make them IL 2-reactive. Neuraminidase treatment reduced the concentration of LA required to mediate both effects. Neuraminidase treatment did not alter the overall Con A-binding capacity of T cells, nor did it induce reactivity to IL 2 in the absence of lectin. Furthermore, irradiated, neuraminidase-treated T cells served as accessory cells (AC) in the induction of responsiveness to IL 2, but not for production of IL2, which depends on Ia+ AC. Finally, Lyt-2- neuraminidase-treated peripheral T cells responded in the same fashion as whole T cell populations, indicating that at least some T cells of the helper phenotype need not interact with Ia+AC for the induction of IL 2 responsiveness.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002449:Cell Aggregation; D002478:Cells, Cultured; D003208:Concanavalin A; D004261:DNA Replication; D005260:Female; D007376:Interleukin-2 / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D009439:Neuraminidase; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014020:Tissue Extracts / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D014020:Tissue Extracts; D003208:Concanavalin A; D009439:Neuraminidase