Transduction of human melanoma cells with the gamma interferon gene enhances cellular immunity.

Human tumor cells transduced with the gamma interferon (gamma IFN) gene are currently used in specific active immunotherapy protocols to enhance the antitumor immune responses of cancer patients. This in vitro study was undertaken to examine the initial events in the cellular immune response that may occur following the administration of the gamma IFN-transduced cell vaccine. Human melanoma tumor cell lines were transduced with a MoMLV-based retroviral vector carrying the human gamma IFN gene. The transduced cells expressed the cytokine gene, secreted biologically active gamma IFN, and exhibited enhanced expression of MHC class I and class II (HLA-DR), and ICAM-1 surface antigens. The gamma IFN-transduced and corresponding parental melanoma cells were used for the induction of short-term lymphocyte cultures. Peripheral blood lymphocytes or lymph node cells from 20 melanoma patients were stimulated for 5 to 15 days with autologous or MHC class I-matched allogeneic parental or gamma IFN-transduced melanoma cells. Seven of the 20 lymphocyte cultures showed substantial increases in lytic activity following stimulation with the transduced melanoma cells in comparison to control lymphocyte cultures stimulated with unmodified parental melanoma. The cytolytic activity stimulated with gamma IFN-modified melanomas was mediated partly by MHC-restricted cytotoxic T lymphocytes and partly by NK cells. Lymphocyte cultures that displayed increases in cytotoxicity after stimulation with the gamma IFN-transduced melanoma cells also exhibited enhanced expression or induction of one or more of the following lymphokines: IL-4, IL-1 alpha, IL-1 beta, gamma IFN, and TNF-alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of the growth of human melanoma metastases in nude mice by melanoma-specific murine monoclonal antibody.

The administration of anti-melanoma murine monoclonal antibody (MAB) 16.C8 (IgG2a) to nude mice bearing established human melanoma lung or liver metastases resulted in a significant inhibition of tumour growth. A total dose of 2 mg of affinity purified 16.C8 caused complete inhibition of tumour growth in 89 and 100% of animals in the liver and lung model, respectively. In contrast, a significant tumour growth was found in most control animals which received an irrelevant IgG2a MAB or 2% human serum albumin in Hanks Balanced Salt Solution (HBSS). The MAB was most effective when treatment was started on day 1 or 4 following tumour inoculation. When the 16.C8 MAB treatment was delayed 7 or 14 days, 33 and 67% of 16.C8 treated animals, respectively, developed tumours. The MAB-mediated anti-tumour activity appeared to be dose dependent, and the effect of a suboptimal dose was potentiated by the concomitant administration of recombinant interleukin 2 (rIL-2). Recombinant IL-2 alone in a similar dose did not elicit comparable anti-tumour activity. Moreover, the MAB 16.C8 inhibited tumour growth in irradiated animals which may suggest the involvement of host-radioresistant cellular elements in the 16.C8 antibody-mediated anti-tumour activities in nude mice. These results suggest that MAB 16.C8 alone or combined with rIL-2 may prove useful in the immunotherapy of metastatic melanoma.

Generation of human IgG, IgA, and IgM anti-melanoma monoclonal antibodies utilizing lymphocytes of an actively immunized melanoma patient.

Active specific immunotherapy with irradiated allogeneic melanoma cells has been shown to enhance the humoral immune response in melanoma patients. An increased titer of melanoma-binding antibodies was demonstrated in sera of immunized patients. Lymph node cells and splenocytes isolated from an actively immunized melanoma patient were fused with the human-murine heteromyeloma cell lines SHMD-33, SPM4-0, and SBC-H20. A group of human anti-melanoma monoclonal antibodies (MABs) were generated from the SHMD-33 fusion. Isolated MABs (one IgG2, one IgA, and two IgM) have been stable in cultures for more than 12 months and have produced human immunoglobulins at 0.2-0.9 Ug/ml/day. As shown by solid phase radioimmunoassays, the MABs react with autologous tumor cells and allogeneic melanoma tumors, including the cell line that was used for immunotherapy. In immunocytochemical assays, all four MABs react with a number of melanoma tumor cell lines. The IgG2 and IgA MABs stained preferentially melanoma tumor cells. In contrast, the IgM MABs cross-reacted with a broad panel of tumor cells from colon, prostate, pancreas, lung, and other human tumors. The MABs appear to be directed to intracellular rather than membrane-associated antigens as shown by immunofluorescence assays on live and permeabilized cells. The IgG2 antibody recognizes a 70 kDa antigen in melanoma cell lysates by Western immunoblotting. The target antigens for the other MABs have not yet been defined. Stability in culture and strong binding to melanoma tumor cells provide the basis for evaluating the potential of these human MABs. The IgG2 MAB, in particular, may prove useful for diagnostic and therapeutic applications in humans.(ABSTRACT TRUNCATED AT 250 WORDS)