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)

Human anti-mouse antibody response in cancer patients following single low-dose injections of radiolabeled murine monoclonal antibodies.

We examined the human anti-mouse antibody (HAMA) response in 61 cancer patients following a single, diagnostic injection of any one of ten 111In conjugated murine monoclonal antibodies. Between 1 and 22 mg of antibody containing 1-5 mCi 111In was administered. The populations studied included 30 patients with colorectal carcinoma (four different antibodies), 22 with malignant melanoma (four antibodies), and nine with prostate cancer (two antibodies). Forty-one percent of the patients developed HAMA within 14 days. Three patients (5%) developed an IgM response, five patients (8%) developed an IgG response, and 17 patients (28%) developed both IgM and IgG. Only 27% of the patients with colon cancer developed HAMA, compared to 55% of the melanoma patients and 56% of the prostate cancer patients. There were no correlations among injected dose, various clinical parameters, and HAMA response. There were variations in the HAMA response to different monoclonal antibodies, but population samples were too small to infer significance. Most of the HAMA responses had a significant proportion of idiotypic or isotypic specificity. Only 1/6 patients who were HAMA negative after the first infusion developed HAMA following subsequent infusions of the same monoclonal antibody. Our data demonstrate that a significant percent of cancer patients develop HAMA following a single, low-dose injection of a radiolabeled monoclonal antibody for diagnostic purposes. This may have important implications for the future therapeutic use of monoclonal antibodies in such patients.

Mechanisms of human CD5 modulation and capping induced by murine monoclonal antibody T101.

We have previously demonstrated that the murine monoclonal antibody T101 induces antigenic modulation when infused into patients with chronic lymphocytic leukemia and cutaneous T-cell lymphoma. In this paper, we extend our studies of T101-induced modulation and compare it to T101-induced capping. We found that, in contrast to antigenic modulation, capping occurred only in the presence of secondary anti-mouse IgG antisera and was altered by drugs that affect the cellular cytoskeleton or energy metabolism. F(ab')2 fragments of T101 induced antigenic modulation with kinetics similar to those of intact T101, but Fab-induced modulation proceeded more slowly and required the continual presence of Fab throughout the incubation. Experiments with radioiodinated T101 demonstrated that initial internalization of the antibody is followed by rapid efflux of intact, immunoreactive T101 from the cells. These data indicate important differences between capping and modulation and suggest that these two phenomena proceed by different mechanisms. More importantly, the data have implications for the potential therapeutic use of monoclonal antibody immunoconjugates.