CD4+ T cells require two signals to produce maximal amounts of IL-2, i.e., TCR occupancy and an unidentified APC-derived costimulus. Here we show that this costimulatory signal can be delivered by the T cell molecule CD28. An agonistic anti-CD28 mAb, but not IL-1 and/or IL-6, stimulated T cell proliferation by tetanus toxoid-specific T cells cultured with Ag-pulsed, costimulation-deficient APC. Furthermore, the ability of B cell tumor lines to provide costimulatory signals to purified T cells correlated well with expression of the CD28 ligand B7/BB-1. Finally, like anti-CD28 mAb, autologous human APC appeared to stimulate a cyclosporine A-resistant pathway of T cell activation. Together, these results suggest that the two signals required for IL-2 production by CD4+ T cells can be transduced by the TCR and CD28.
CITATION STYLE
Jenkins, M. K., Taylor, P. S., Norton, S. D., & Urdahl, K. B. (1991). CD28 delivers a costimulatory signal involved in antigen-specific IL-2 production by human T cells. The Journal of Immunology, 147(8), 2461–2466. https://doi.org/10.4049/jimmunol.147.8.2461
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