Possible association between IL-2 receptors and class I HLA molecules on T cells

In the process of evaluating murine hybridomas for an antibody to the β-subunit of the IL-2R (p70) we identified an antibody that immunoprecipitated a 55- to 57-kDa complex from cross-linked lysates. We demonstrate that this complex is composed of IL-2 (15.5 kDa) cross-linked to the H chain of HLA class I (40 to 42 kDa), suggesting a molecular interaction between HLA class I molecules and IL-2R. Although the exact role of this association remains to be determined, the specific cross-linking of IL-2 to HLA class I Ag is intriguing in view of published claims for a role of HLA class I in OKT3-induced lymphocyte proliferation and in NK cell lytic activity.