IL-12Rβ1 lacking exon 2 is expressed on the membrane. Expression of IL-12Rβ1 on the cell membrane of activated T cells from an IL-12Rβ1^−/− patient was analyzed with the antibody DU-1. (A) Untransduced cells. (B) Cells transduced with GFP vector only. (C) Cells transduced with a wild-type IL12RB1 construct. (D) Cells transduced with the IL12RB1 construct lacking exon 2.