Abstract
A CD4(+) T cell clone (HC/2G-1) was established by stimulating peripheral blood T cells from a patient with renal cell carcinoma (RCC) with dendritic cells preincubated with the autologous apoptotic renal tumor line in the presence of IFN-alpha. It recognizes the autologous RCC and most allogeneic RCC lines by IFN-gamma release (10 of 11 lines) and lysis (9 of 10 lines), but does not recognize multiple EBV B cells or fibroblasts. It shows little or no recognition of a panel of melanomas, breast cancers and non-small-cell lung cancers. Phenotypically, HC/2G-1 is CD3(+)CD4(+) TCR alphabeta(+), but CD161(-)CD16(-)NKG2D(-). Tumor recognition by clone HC/2G-1 was not blocked by Abs to HLA class I or class II, but was significantly reduced by anti-TCR alphabeta Ab. Furthermore, tumor recognition was beta(2)-microglobulin-independent. HC/2G-1 does not use a Valpha or Vbeta described for classical NKT cells, but rather Valpha14 and Vbeta2.1. Allogeneic T cells cotransfected with mRNAs encoding the alpha and beta chains of the HC/2G-1 TCR recognized renal tumor lines, demonstrating that tumor recognition is TCR-mediated. Interestingly, TRAIL appears to play a role in tumor recognition by HC/2G-1 in that reactivity was blocked by anti-TRAIL Ab, and soluble TRAIL could enhance IFN-gamma secretion by HC/2G-1 in response to renal tumors. Our findings suggest that clone HC/2G-1 represents a novel type of CD4(+) cell that has broad TCR-mediated recognition of a determinant widely expressed by RCC.