Xenogeneic recognition of tumour specific plasma membrane antigens derived from mouse lymphoma cells

Rabbit antisera were prepared to two mouse ascitic lymphomas, one of them being highly immunogenic, the other one weakly immunogenic in syngeneic hosts. A comparison was made between antisera raised with intact cells and antisera raised with cell-free fractions composed of purified large plasma membranes. The antisera were tested in vitro for their lytic capacity by the ⁵¹Cr-release technique, and in vivo for their capacity to protect syngeneic mice against a tumour challenge. The antisera were used unabsorbed, absorbed with syngeneic mouse tissue, and also after passage through syngeneic animals. The antisera with the highest specificity for the respective tumour in mice were those raised by plasma membranes derived from the strongly immunogenic tumour. Lysis in the ⁵¹Cr test corresponded roughly with these findings. Xenogeneic recognition of tumour distinct antigens as well as the therapeutic value of xenogeneic antisera against established lymphomas growing in the ascitic form are discussed.