@article {542651, title = {A role for the B7-1/B7-2:CD28/CTLA-4 pathway during negative selection.}, journal = {J Immunol}, volume = {170}, number = {11}, year = {2003}, month = {2003 Jun 1}, pages = {5421-8}, abstract = {Although costimulation plays an important role in activating naive T cells, its role in negative selection is controversial. By following thymocyte deletion induced by endogenous superantigens in mice lacking B7-1 and/or B7-2, we have identified a role for both B7-1 and B7-2 in negative selection. Studies using CD28-deficient and CD28/CTLA-4-double-deficient mice have revealed that either CD28 or another as yet undefined coreceptor can mediate these B7-dependent signals that promote negative selection. Finally, CTLA-4 delivers signals that inhibit selection, suggesting that CTLA-4 and CD28 have opposing functions in thymic development. Combined, the data demonstrate that B7-1/B7-2-dependent signals help shape the T cell repertoire.}, keywords = {Animals, Antigens, CD, Antigens, CD28, Antigens, CD40, Antigens, CD80, Antigens, CD86, Antigens, Differentiation, Cell Differentiation, Clonal Deletion, CTLA-4 Antigen, Down-Regulation, Enterotoxins, Lymphocyte Depletion, Membrane Glycoproteins, Mice, Mice, Inbred BALB C, Mice, Knockout, Signal Transduction, Staphylococcus aureus, Superantigens, T-Lymphocyte Subsets}, issn = {0022-1767}, author = {Buhlmann, Janet E and Elkin, Sheryl Krevsky and Sharpe, Arlene H} }