Regulation of IL-2 beta receptor expression and beta-chain mRNA by human thymocytes.
The high affinity form of the human IL-2 receptor (IL-2R) has two known components, the IL-2R alpha (p55) and the IL-2R beta chain (p75). We have previously shown that recombinant IL-2 (rIL-2) could induce the expression of the alpha-chain (p55) on T cells and thymocytes, and increase this expression following suboptimal activation with concanavalin A (Con A) in combination with IL-2. An increase in the accumulation of IL-2R alpha-specific mRNA induced by rIL-2 in T cells and thymocytes had also been documented. We report here that the expression of IL-2R beta on the cell surface can be demonstrated on human thymocytes by the binding of Mik beta1, a MoAb directed against an epitope of the beta-chain. The IL-2R beta chain is constitutively expressed on freshly isolated thymocytes; this expression can be increased in thymocytes activated with Con A in combination with IL-2 or tetradecanoylphorbol 13-acetate (TPA). Blocking the formation of high affinity receptors with a MoAb directed against the alpha-chain of the receptor results in an increase in the display of IL-2R beta as evidenced by binding of MoAb Mik beta1. The accumulation of IL-2R-beta-specific mRNA is observed in freshly isolated thymocytes and it is increased in thymocytes cultured with rIL-2 alone, with Con A, and further enhanced by the addition of rIL-2 in combination with Con A or with TPA. Cyclosporine (CsA), which inhibits the accumulation of lymphokine-specific mRNA of thymocytes, does not inhibit the induction of the accumulation of IL-2R beta-specific mRNA. This is analogous to its effect on the expression of the alpha-chain (p55), and the accumulation of alpha-chain-specific mRNA.
Reem
G H
GH
Department of Pharmacology, New York University Medical Center, NY 10016.
Han
X
X
Marcelli
A
A
D000818:Animals; D015152:Blotting, Northern; D002675:Child, Preschool; D016572:Cyclosporine / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D007223:Infant; D007376:Interleukin-2 / Q000494:pharmacology; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis*; D015375:Receptors, Interleukin-2 / Q000032:analysis* / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology*
D007376:Interleukin-2; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D016572:Cyclosporine