Embryo‐derived teratocarcinoma. III. Development of tumors from teratocarcinoma‐permissive and non‐permissive strain embryos transplanted to F 1 hybrids

Seven‐day‐old mouse embryos of two teratocarcinoma‐permissive (C3H and BALB/c) and two teratocarcinoma‐non‐permissive (C57BL/6 and AKR) strains were transplanted to their F 1 hybrids to determine the role of the genetic background of the recipient animals in controlling embryo‐derived teratocarcinogenesis. The yield of teratocarcinomas in F 1 hybrid recipients of embryonic grafts was either identical with the yield in syngeneic recipients or increased or decreased, depending on the strain of the embryo and the F 1 hybrid combination. In certain hybrids, the yield of malignant tumors remained the same as in the syngeneic recipients but the F 1 hybrids exerted a stimulatory effect on tumor growth and the tumors weighed more than those in syngeneic recipients. A matroclinous effect was also seen in certain hybrids. These data indicate that embryo‐derived teratocarcinogenesis in histocompatible F 1 mice depends on the genetic background of adult recipients. The teratocarcinogenic potential of non‐permissive and permissive strain mouse embryos can be modified by choosing appropriate F 1 hybrids for embryonic transplantations.