Induction of delayed hypersensitivity reactions in cancer patients by cholesterol-hemisuccinate-treated autologous tumor cells.

Cholesterol-hemisuccinate (CHS) incorporated into tumor cells increases membrane lipid microviscosity and confers enhanced immunogenicity, which can be manifested by delayed hypersensitivity skin reactions. Skin testing was performed in 30 patients with various advanced malignant tumors. Patients were given intradermal injections of 10(6) autologous, irradiated, CHS-treated tumor cells. Control injections consisted of untreated irradiated tumor cells, CHS-treated autologous normal peripheral lymphocytes, or CHS-treated autologous normal tissues. For all patients tested, strongly positive skin reactions were observed when CHS-treated tumor cells were used. Untreated irradiated cells gave negative or very weakly positive reactions. In all cases, normal CHS-treated cells did not elicit any observable skin reactions. CHS-treated cells may have unmasked tumor-associated antigens to which patients may elicit immunologic responses.