Gamma (immune) interferon produced by leukocytes from a patients with a T cell proliferation disease.
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Biomedical subjects
Publications and source records attributed to T L Gerrard.
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The role of human neutrophils as effector cells in host resistance to neoplasia was investigated. Neutrophil cytotoxicity was quantitated in an in vitro assay measuring release of [3H]thymidine from prelabeled human tumor cells. Neutrophils were consistently cytotoxic and cytostatic to the adherent tumor lines T24 (a transitional cell carcinoma of the bladder), LR (melanoma), and simian virus 40-transformed WI-38 VA 13 fibroblasts and to the nonadherent lymphoid tumor lines K562, Raji, and CEM. Maximum cytolysis and cytostasis occurred at 72 hours. Neutrophils were selectively cytotoxic for tumor cells and generally did not kill normal human fibroblasts. Selected protease inhibitors did not inhibit neutrophil cytotoxicity and neutrophil lysates were ineffective in killing tumor targets.
This study was aimed at characterizing the parameters which regulate human monocyte-mediated cytotoxicity to tumor cells as well as characterizing the target cell specificity, kinetics, etc., of the cytotoxic mechanism. Normal human peripheral blood monocytes were cytotoxic to tumor cells in an in vitro assay, measuring release of [3H] thymidine from human target cells. Monocyte cytolysis was observed with several adherent tumor lines including T24, a bladder cancer line; LR, a melanoma line; and an SV40-transformed W138 fibroblast line, with maximal cytolysis observed at 72 h. Lymphokines were not required to induce and only infrequently enhanced monocyte cytotoxicity. Prolonged exposure of monocytes to lymphokines or in vitro culturing of monocytes prior to lymphokine exposure did not alter the monocytes response to lymphokine signals with respect to cytotoxicity. Lymphokines induced monocytes to exhibit enhanced spreading, suggesting that monocytes were susceptible to lymphokine signals but that the development of cytolytic function was independent of lymphokines. In contrast to the cytolysis of adherent tumor cells, monocytes were less effective in killing the non-adherent lymphoid target cells K562, Raji, and CEM. Monocytes were selectively cytotoxic to tumor cells and generally did not kill normal human fibroblast cell lines or PHA-stimulated lymphocytes. Monocytes from cancer patients exhibited normal cytotoxicity to several human tumor lines. Plasmas from some cancer patients were inhibitory to cytotoxicity mediated by both autologous monocytes and normal monocytes.
Cells of Escherichia coli will reduce sodium selenite to elemental selenium. Examination by electron microscopy of E. coli cultures grown in the presence of sodium selenite show selenium deposited on the cell membrane and cell wall but not in the cytoplasm.