Immuno‐selection In vivo of H‐2D phenotypic variants from a metastatic clone of sarcoma cells results in cell lines of altered metastatic competence

To find out whether manipulation of H‐2 expression on metastatic cells could alter their metastatic properties, we immunoselected in vivo H‐2 antigen variants from a metastatic clone of the T10 sarcoma [originating in a (C57BL/6 XC3H.eB)F1 mouse] and tested their metastatic capacity. The unselected metastatic cells (IE7) were previously found to express H‐2D^b and H‐2D^k antigens, but they did not express the H‐2K antigens of either parental haplotype. Transplantation of IE7 cells into C57BL/6J irradiated mice resulted in loss of H‐2D^k expression and a reduction in H‐2D^b antigen density. Further transplantation of these cells into non‐irradiated C57BL/6J mice led to a total loss of H‐2 expression. The cells concomitantly lost their metastatic potency. Immunoselection of IE7 cells in C3H.eB irradiated and non‐irradiated mice resulted in cells which were H‐2D^k‐positive but H‐2D^b‐negative. Cells of these selected variants not only retained their metastatic potential, but in fact were far more metastatic than the unselected IE7 cells. Thus, changes in H‐2 expression on tumor cells may alter their metastatic potential. In the case of T10 cells, H‐2D^k expression seems to be directly involved in their metastatic capacitiy.