Paper No. 2 in the Symposium on Immunogenetics and Carcinogenesis The Immunogenetics of Tumor Transplantation*

The current program of transplantation re search at the Jackson Laboratory is based on two approaches: one immunological in conception and, probably, in fact; the other genetic. As yet the only certain connection between the two is their common dependence on transplantable tumors. Some preliminary evidence, however, points to other interesting relationships. This has been a joint project. Much of the work has been done by Dr. Kaliss and Dr. Borges. At an earlier date, Dr. Cloudman also participated. Drs. Molomut and Spain have collaborated in certain aspects of the undertaking. I shall also review some results, possibly related to ours, obtained at other laboratories. The genetic investigations have been concerned with the detailed analysis of the genes determining susceptibility and resistance to transplants. I will not describe the methods used, since these are quite technical, but instead will give a brief sum mary of conclusions. One genetic locus has turned out to be particu larly important in determining susceptibility and resistance to transplants. This locus has been termed histocompatibility-2 or H-2 (25). It is a "strong" locus, that is to say, a difference at this