|| Checking for direct PDF access through Ovid
A new group of congenic resistant (CR) lines of mice, differing one from another primarily by differences at single histocompatibility loci, has been produced by appropriate crosses. One parent in every case was strain C57BL/10 which provides the genetic background for the lines. For the other parent, with certain exceptions which do not concern us here, lines were selected which, like C57BL/10, have been typed as H-2b. The lines were inbred strain 129/Rr, and congenic strains C.B6, with H-2b on a BALB/c background, and D2.W, with H-2b on a DBA/2 background. Of the 20 CR lines produced from these crosses, seven are described for the first time in this paper. These serve to identify five new histocompatibility loci, herewith assigned the symbols H-7, H-8, H-9, H-10, and H-11. These lines vary substantially in the barrier which they oppose to C57BL/10 leukemic homografts, but except for line B10.C(47N) which differs from C57BL/10 at H-7, are all substantially “weaker” than lines characterized by the previously identified loci. They differ not only in “strength” of the allogeneic barrier, but also in the manifestation of this barrier in the two sexes. There are always more deaths from leukemic allografts in males than in females, but the difference is relatively slight in strain B10.129(9M), differing from C57BL/10 at H-10, and very marked in strain B10.C(45N), differing from C57BL/10 at H-9. A summary of the lines used in this study will be found in Table 7.