CD4(+), HLA class I-restricted, cytolytic T-lymphocyte clone against primary malignant melanoma cells

The involvement of HLA-class I in target cell lysis by CD4(+) cytolytic T c ells (CTL) has been a controversial issue. A CTL clone of CD4 phenotype was derived from the peripheral blood lymphocytes of a patient with primary me lanoma. The CTL clone stably lysed the autologous primary melanoma cells fo r approximately 9 months in culture. Both the V alpha 2/ V beta 8 T-cell re ceptor and CD4 were involved in CTL cytotoxicity. Of a large panel of allog eneic primary and metastatic melanoma or colorectal carcinoma cells, autolo gous and allogeneic Epstein-Barr virus-transformed B cells and autologous f ibroblasts, only allogeneic metastatic melanoma cells matched with the auto logous tumor cells for HLA-class I (B57[17]) were lysed and induced IFN-gam ma secretion by the CTL clone. Lysis of the autologous tumor cells was sign ificantly blocked by monoclonal antibody to HLA-B17. Importantly, allogenei c, HLA-class I- and class Ii-unmatched melanoma cells were lysed by the CTL only following transfection of the cells with B57[17] cDNA. Our results pr ovide direct evidence for the involvement of both CD4 and HLA-class I in tu mor cell lysis by CD4(+) CTL. Int. J. Cancer 85:253-259, 2000. (C) 2000 Wil ey-Liss, Inc.