passages.id: split_9_validation_1391_passage
passages.type: progene_text
passages.text: Thymic CD4 + T-cell blasts , established by stimulating human thymic CD1a - CD4 + T cells with TSST-1 in vitro , produce a low level of interleukin-2 after restimulation with TSST-1 , whereas TSST-1 - induced adult peripheral blood ( APB ) CD4 + T-cell blasts produce high levels of interleukin-2 .