CD28 and CTLA-4 expressions in the process of mice' T-cell inefficiency induced by staphylococcal enterotoxin A / 解放军医学杂志

ABSTRACT

Objective To explore the characteristics and regulations of CD28 and CTLA-4 expressions in the process of mice' T-cell inefficiency induced by staphylococcal enterotoxin A(SEA).Methods Twelve mice were averagely divided into three groups(4 each).The mice in group 1 received single injection of SEA,and the mice in group 2 and 3 received SEA injection twice and three times,respectively,with a 3 days interval.Mice were sacrificed at day 1,3,7 and 14 after the last injection,and then the splenic lymphocytes were isolated.The expressions of CD28 and CTLA-4 in cellular membrane and the intracellular expressions of CTLA-4 and IL-2 were detected with flow cytometry.Results In group 1,the CD28 expression in cellular membrane and the intracellular expression of IL-2 were significantly up-regulated,while the CTLA-4 expressions both in cellular membrane and intracellular expression were lower with no obvious changes.In group 2,the expressions of both CD28 and IL-2 were up-regulated slightly,the expressions of CTLA-4 increased significantly both in cellular membrane and intracellular expression,even more increase was the intracellular CTLA-4 expression.In group 3,the expressions of CD28 and CTAL-4 in cellular membrane and the intracellular CTLA-4 expression declined,and at day 7 the intracellular IL-2 expression was undetectable.Conclusions SEA may obviously promote the activation of naive T-cells when initially used to induce the splenic lymphocytes,while multiple stimulations(e.g.3 times) of SEA may lead T-cells to anergy.On the process of inefficiency,the declined IL-2 production may be closely related to the down-regulation of CD28 expression;the up-regulation of CTLA-4 expression may profit inducing inefficiency,but is not on the maintenance of inefficiency.