@article {542841,
	title = {The role of B7 costimulation in CD4/CD8 T cell homeostasis.},
	journal = {J Immunol},
	volume = {164},
	number = {7},
	year = {2000},
	month = {2000 Apr 1},
	pages = {3543-53},
	abstract = {The effect of B7-mediated costimulation on T cell homeostasis was examined in studies of B7-1 (CD80) and B7-2 (CD86) transgenic as well as B7-deficient mice. B7 overexpression in transgenic mice resulted in marked polyclonal peripheral T cell hyperplasia accompanied by skewing toward an increased proportion of CD8 single-positive cells and a decreased proportion of CD4 single-positive cells in thymus and more markedly in peripheral T cells. B7-induced T cell expansion was dependent on both CD28 and TCR expression. Transgenic overexpression of B7-1 or B7-2 resulted in down-regulation of cell surface CD28 on thymocytes and peripheral T cells through a mechanism mediated by intercellular interaction. Mice deficient in B7-1 and B7-2 exhibited changes that were the reciprocal of those observed in B7-overexpressing transgenics: a marked increase in the CD4/CD8 ratio in peripheral T cells and an increase in cell surface CD28 in thymus and peripheral T cells. These reciprocal effects of genetically engineered increase or decrease in B7 expression indicate that B7 costimulation plays a physiological role in the regulation of CD4+ and CD8+ T cell homeostasis.},
	keywords = {Animals, Antigens, CD, Antigens, CD28, Antigens, CD80, Antigens, CD86, Antigens, Differentiation, CD4-CD8 Ratio, CD4-Positive T-Lymphocytes, CD8-Positive T-Lymphocytes, CTLA-4 Antigen, Down-Regulation, Homeostasis, Hyperplasia, Immunoconjugates, Lymphocyte Activation, Lymphoid Tissue, Membrane Glycoproteins, Mice, Mice, Congenic, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Mutant Strains, Mice, Transgenic, Phenotype, Receptors, Antigen, T-Cell, Receptors, Antigen, T-Cell, alpha-beta, T-Lymphocyte Subsets},
	issn = {0022-1767},
	author = {Yu, X and Fournier, S and Allison, J P and Sharpe, A. H. and Hodes, R J}
}
