Abstract
The transplantability of the CBA tumor-I was studied in mice of pure and hybrid strains. The tumor under study is one of spontaneous mammary adenocarcinomas originally developed in a purely inbred mouse of CBA/Mk strain.
It was found that this tumor was wholly transplantable to mice of original CBA/Mk strain giving 100 per cent lethal takes. For mice of EM-agouti and C3H/He strains which are the same in origin to the CBA/Mk strain, the tumor showed a relatively high transplantability giving over 85 per cent lethal takes. In striking contrast, the tumor gave low- or non-transplantability, showing 0 to 5.3 per cent takes (Table 1) for mice of the following 10 strains: A/He, AKR/Ms, C57BL/6, DBA, dd, DM/Mk, EM-black, MT, NH and Swiss-albino. From the above results, it is evident that the CBA tumor-I here concerned is one of highly strain-specific tumors, and that the CBA/Mk, C3H/He and EM-agouti mice are highly susceptible to that tumor, while the mice of other 10 strains are non-susceptible.
The results of tumor transplantation tests with F1, F2 and backcross hybrids derived between resistant strains (C57BL/6 and EM-black) and a susceptible strain (CBA/Mk) furnished an evidence indicating that the CBA tumor-I possessed at least one histocompatibility factor (Table 2).
