An investigation of cellular components released from human renal cancer and foetal kidney xenografts in nude mice (nu/nu) by cross-immunization of hairy littermate relatives.

The release of components from human kidney tumour xenografts (GYL) and human foetal kidney explants maintained in nude mice has been studied. The GYL tumour released antigens into the serum which could be detected by the generation of antibodies following cross-immunisation of closely related hairy litter mate (HLM) mice. The production of anti-GYL antibody was monitored by an I125 binding assay using viable GYL tumour cells. In 2/16 hairy litter mate mice, cell surface antibody binding by GYL cells was twice that found with 8 other human tumour cell lines (including 2 other kidney cancer cell lines). Absorption of these antisera with 10(7) GYL tumour cells completely abolished this response, where 50%, 38% and 25% of activity remained following absorption with; a normal kidney cell line, a homogenate of normal kidney and a mixed pool of human tumour cells. Six out of 8 GYL tumour bearing nude mice tested had elevated plasma levels of HCG. Absorption of the HLM antisera with an excess of commercial HCG abrogated I125 binding by only 15%, suggesting that antibody production was not directed primarily against ectopic HCG.