Expression of the interleukin 2 receptor beta chain (p75) in renal transplantation--applicability of anti-interleukin-2 receptor beta chain monoclonal antibody.

The interaction of interleukin 2 with specific cellular receptors plays an essential role in the allostimulated proliferation and differentiation of T cells. Recent chemical linking studies have demonstrated that the human high-affinity IL-2 receptor is a membrane complex composed of at least two distinct subunits, which are the p55 (alpha-chain) and p75 (beta-chain) subunits. The IL-2R beta chain is supposed to play a role in the signal transduction of IL-2, but the exact mechanism is still unknown. In this study, we investigated the effects of a newly established anti-IL-2R beta chain monoclonal antibody (MoAb, TU-27) on the induction of cytotoxic T lymphocytes (CTLs) using the cell-mediated lympholysis (CML) assay. TU-27 in combination with H-31, a MoAb directed against the IL-2R alpha chain, produced inhibition of cytotoxicity, while TU-27 alone could not inhibit cytotoxicity, while TU-27 alone could not inhibit cytotoxicity at any concentration. TU-27 plus H-31 prevented the expansion of CD4+ cells and CD8++ cells in mixed lymphocyte culture (MLC). Furthermore, we examined the serial changes in the expression of the IL-2R beta chain on peripheral blood lymphocytes from renal transplant recipients using two-color immunofluorescence flow cytometry, so as to investigate correlations between IL-2R beta chain expression and the occurrence of allograft rejection. Here, we report that the IL-2R beta chain is expressed on CD4-positive (CD4+) cells and strongly CD8-positive (CD8(+)+) cells in association with acute rejection, indicating that IL-2R beta chain expression appears to increase on alloreactive T cells.