Immunological responses against an autologous human hepatocellular carcinoma cell line

We performed a detailed analysis of immune responses in a hepatocellular carcinoma (HCC) cell line and effector cells obtained from a patient with HCC. We examined the cytotoxic activity of natural killer (NK) cells, lymphokine-activated killer (LAK) cells and cytotoxic T lymphocytes (CTL) against an autologous tumour cell line (SUHC-1) to investigate the immune mechanism of human lymphocytes against HCC cells. Cytotoxic T lymphocytes were induced by co-culturing of peripheral blood lymphocytes (PBL) and SUHC-1 cells, mixed lymphocyte and tumour cell culture (MLTC). The susceptibility of SUHC-1 to NK and LAK cells was similar to that of other allogeneic cell lines, such as K562, PLC/PRF/5 and Mahlavu. Effector cells induced in the primary MLTC had high cytotoxic activity but were not specific for SUHC-1. Cytotoxic T lymphocytes with specific activity against SUHC-1 were induced after PBL were stimulated five times at 7-10 day intervals with SUHC-1 and low-dose recombinant interleukin-2 (rIL-2), suggesting that as the culture progressed, broadly reactive effector cells disappeared and specific effector cells survived. The specific effector cells were identified as CD3+/CD4+ and CD3+/CD8+ T-lymphocyte subsets. The recognition mechanisms of CD3+/CD4+ CTL remain unresolved because the cytotoxicities were not inhibited by anti-CD4 and anti-major histocompatibility complex (MHC) class II monoclonal antibodies (MoAb). Treatment of cells with anti-CD3, anti-CD8 and anti-MHC class I MoAb partially inhibited lysis. These results demonstrated that the T-cell receptor (TCR)/CD3 complex appeared to be involved in SUHC-1 specific antigen recognition and antigen recognition of CD3+/CD8+ CTL was MHC class I restricted.