Inhibition of the YC8 lymphoma growth by alloimmunization with normal cells

It has been shown that murine tumors may express alien histocompatibility antigens encoded both by the MHC or by non-H-2 genes. In vivo immunization with allogeneic normal tissues was shown to protect syngeneic mice against neoplastic growth of sarcomas expressing the relevant antigen(s). With a similar approach, Zarling et al. could elicit a significant cell-mediated killing on autologous neoplastic targets by peripheral lymphocytes of certain patients sensitized in vitro to a pool of allogeneic normal cells. A comparable study was recently reported by the same group of workers in which solid murine tumors also appeared to be sensitive to the in vitro action of both T or non-T effectors generated by pool alloimmunization. In addition, Bortin et al. have described an in vivo system in which the development of AKR leukemias could be successfully prevented by grafting bone marrow of alloimmune H-2-compatible mice. We felt it important, therefore, to verify whether a similar antitumor activity directed to other types of lymphomas can be raised in vivo by alloimmunization with normal cells. We report here that alloimmunization with normal lymphoid cells of some strains dramatically increases the resistance of BALB/c mice to the growth of a syngeneic Moloney virus-induced lymphoma, YC8, previously shown to lack detectable amounts of alien H-2 antigens.