Effect of autoimmunization with irradiated tumour cells on specific cell-mediated immunity in patients with malignant melanoma

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Autoimmune reactions in uveal melanoma

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Smooth muscle antibody in malignant disease

Smooth muscle antibody at titres of 1/10 or more was found in 54 (67.5%) out of 80 patients with malignant disease and in 9 (20%) out of 46 controls. The incidence of S.M. antibody ranged from 18/30 (60%) in malignant melanoma to 7/8 (83%) in carcinoma of the ovary. The presence of this antibody is possibly related to changes in the malignant cell membrane.A new antibody directed at an antigen presumed to be located in bile canaliculi among other sites is described.

Complement Dependent Inhibition of RNA Synthesis in Malignant Melanoma Cells

The RNA synthesis of human melanoma cells in suspension is estimated by the uptake of tritiated uridine (3HU) after incubation with autologous, homologous serum from other patients with malignant melanoma and normal control serum with active and inactivated added complement. The total amount of labelled precursor incorporated is determined by extracting the acid/alcohol soluble material, dissolving the final precipitate in a solvent and mixing with scintillation fluid. Each pot is then counted in a Packard-3 liquid scintillation counter. The pulses recorded reveal the rate of RNA synthesis in the cells after incubation with the tested sera and inversely indicate the extent of the cytotoxic action exerted by serum antibodies upon the target cells in the presence of active complement. A test is positive when the uptake of 3HU in a pot containing the precipitate of autologous and/or homologous action is at least 20 per cent less than the average pulses for the control pots.

Tumor cell suspensions from 44 melanoma patients were tested against their own sera, against the sera from other melanoma patients and against sera from normal healthy individuals. Autologous cytotoxic effect was recorded in 11 cases (approximately 30 per cent of the cases). Homologous positivity was displayed in 5 cases. Cytotoxic action, being quantitatively determined, diminished with the spread of the disease.

In vitro detection of cytotoxic cellular immunity against tumor-specific antigens by a radioisotopic technique

[(3)H]Thymidine-labeled tumor cells are used to evaluate the cytotoxic cellular immune response against tumor-specific antigens; the loss of label due to destruction and detachment of target cells from the surface of the culture vessel is measured. Spleen cells from mice immunized against Moloney virus-induced rhabdomyosarcoma specifically destroyed the sarcoma cells, while cells from normal syngeneic mice did not. Peripheral blood lymphocytes from patients with malignant tumors were specifically cytotoxic to autologous tumor cells and to allogeneic tumor cells histopathologically identical to the autologous tumor, but not to autologous nonmalignant fibroblasts, or to allogeneic tumor cells from a histologically dissimilar tumor. Serum from the same patients specifically protected autologous tumor cells from lymphocyte cytotoxicity. This serum-mediated protection of tumor cells against autologous cellular immunocytotoxicity also extended to histologically identical allogeneic tumor cells. Cross-reactivity of anti-tumor cellular immunocytotoxicity in vitro, and its "blocking" by autologous serum, strongly suggest the presence of common tumor antigens. The antagonism demonstrated in vitro between serum and cellular immunity may explain the continued growth of malignant tumors in the face of demonstrable cellular immunity.

Immunization with irradiated tumour cells and specific lymphocyte cytotoxicity in malignant melanoma

A microculture technique has been adapted to assay the cytotoxic properties of the lymphocytes from patients with malignant melanoma when cultured with their autologous tumour cells. In a series of patients with established melanoma specific autologous cytotoxicity was extremely uncommon, being detectable in only 3 out of the 22 cases studied. This cytotoxicity did not correlate with clinical staging of the disease but may well have been related to tumour volume. By autoimmunization of patients with an irradiated suspension of their own tumour cells the appearance of cytotoxic lymphocytes could be provoked in 5 out of the 12 patients studied. This cytotoxicity was detectable at the end of the first week after the autograft and disappeared by the third week. Cytotoxic lymphocytes did not correlate in any obvious way with the appearance of specific antitumour antibodies detected by immunofluorescence. So far there has been no evidence of a serum factor capable of blocking the lymphocyte cytotoxicity in these patients.The presence and possible significance of cytotoxic lymphocytes in patients with malignant disease is discussed.