Melanoma skin test antigens of improved sensitivity prepared from vesicular stomatitis virus-infected tumor cells.
Crude membrane (CM) extracts from three different cultured human melanoma lines that were "virus-augmented" (infected with vesicular stomatitis virus (VSV) and subsequently inactivated by ultraviolet light) produced positive skin tests in 17 of 20 (85%), 11 of 20 (55%), and 13 of 18 (72%) tests, respectively, performed in 20 melanoma patients. Identical CM extracts from the same melanoma lines that had not been infected with VSV gave positive skin tests in 2 of 20 (10%), 4 of 20 (20%), and 2 of 18 (11%) tests, respectively, performed in the 20 melanoma patients, and no positive tests in the control patients. The 3 virus-augmented extracts were positive in only 2 of 18 (11%), 0 of 18 (0%), and 1 of 17 (6%) control subjects, respectively. The controls consisted of six normal volunteers and 12 patients with cancers other than melanoma. The "virus-augmented" CM extracts thus exhibited markedly greater sensitivity without significant loss of specificity as compared to nonvirus augmented extracts when used as tumor-specific melaonma skin test antigens.