CD4(-LYMPHOCYTES INFILTRATING HUMAN BREAST-CANCER RECOGNIZE AUTOLOGOUS TUMOR IN AN MHC-CLASS-II RESTRICTED FASHION() T)

Tumor-infiltrating lymphocytes (TIL) were derived from primary breast tumors, metastatic lymph nodes and malignant pleural effusions from 34 patients with breast cancer. TIL were cultured for approximately 30 d ays and studied for phenotype, cytotoxicity, and the ability to secret e cytokines in response to autologous tumor stimulation. Tumor specime ns were obtained from two different sites in 7 patients, resulting in 41 samples from which 38 TIL cultures were established. In addition to screening 38 bulk TIL cultures, TIL from 21 patients were separated i nto CD4(+) and CD8(+) subsets and extensively studied. Three CD4(+) TI L were found specifically to secrete granulocyte macrophage-colony-sti mulating factor and tumor necrosis factor a when stimulated by autolog ous tumor and not by a large panel of stimulators (24-34) consisting o f autologous normal cells, allogeneic breast or melanoma tumors and EB V-B cells. This cytokine release was found to be MHC-class-II-restrict ed, as it was inhibited by the anti-HLA-DR antibody L243. These 3 pati ents' EBV-B cells, when pulsed with tumor lysates, were unable to act as antigen-presenting cells and induce cytokine secretion by their res pective CD4(+) TIL. These findings demonstrate that MHC-class-II-restr icted CD4(+) T cells recognising tumor-associated antigens can be dete cted in some breast cancer patients.