Subcellular localization of CD80 receptors is dependent on an intact cytoplasmic tail and is required for CD28-dependent T cell costimulation.

摘要: CD28 provides a major costimulatory signal to T cells when it is cross-linked with mAb, immobilized recombinant ligand (CD80Ig or CD86Ig), ligand-bearing but not bound by specific Fab fragments monomeric ligand. We wanted determine how CD80 could cross-link since expressed as monomer on the surface of APC. found that may interact actin-based cytoskeleton. To test whether interaction cytochalasin B-sensitive cytoskeleton was necessary for cell costimulation through CD28, we constructed tailless form and generated stable transfectants Chinese hamster ovary epithelial Reh B expressing either wild-type molecules. Unlike control CD80, equivalent levels were able provide anti-CD3-induced proliferation, up-regulation CD25 (IL-2Ralpha) expression, induction IL-2 secretion. Thus, cytoplasmic tail apparently required cells. Confocal microscopic studies revealed have different patterns subcellular distribution in both lymphoid Furthermore, contact induces more patching capping CD80-expressing than This suggests region functions localize complexes effective costimulation.