Clonal analysis of cytotoxic and regulatory T cell responses against human melanoma.

T cell-mediated immune response against autologous melanoma cells was analyzed, at population and clonal levels, in 31 patients with recurrent and/or metastatic disease. Fresh PBL and lymph node lymphocytes (LNL) from melanoma-involved nodes were not cytotoxic against the respective melanoma cells. When activated in in vitro coculture (IVC) against the autologous melanoma cells in the presence of IL-2, a majority of the activated PBL and LNL became cytotoxic against the autologous targets.

Protective immunity by chemically modified tumor cell antigens extracted by 3 M KCl.

Tumor antigens from Sarcoma-180 ascites tumor cells were extracted by 3 M KCl before and after treatment with acriflavine. Following dialysis of the extracts against distilled water to remove KCl, the soluble material (antigen) and the precipitate formed during dialysis were collected from the dialysate. Protective immunity of the soluble antigen and the precipitate was evaluated by immunizing mice and subsequent challenge with native tumor cells.

Acriflavine-induced surface changes in three tumor cell types and differential sensitivity to lectins.

Phytohemagglutinin (PHA) and concanavalin A (Con A) were used as probes to detect changes in the cell surface of Dalton's lymphoma, sarcoma-180 and Ehrlich's carcinoma after short in vitro exposure to acriflavine. Dye-treated cells showed enhancement of agglutination both by PHA and Con A, and such enhancement was found to be dependent on the time of exposure and concentration of acriflavine. However, PHA-induced percent agglutination seemed to be much higher than that of Con A among the 3 cell types.