A reappraisal of Mls genetics.

Although the minor lymphocyte stimulatory locus (Mls) system was originally described as a single-locus, multiple-allelic system, allelism among the genes which encode Mlsa, Mlsc and Mlsd has not been demonstrated formally. In this report, genetic linkage between genes encoding Mlsa and Mlsc was studied by testing responses of unprimed T cells, as well as Mlsa- and Mlsc-specific T cell clones, to the progeny of (AKR/J x C3H/HeJ) F1 x B10.BR [(Mlsa x Mlsc)F1 x Mlsb] crosses. In addition, the configuration of Mls genes expressed by CBA/J (Mlsd) was evaluated by examining the response pattern of a panel of Mlsd-specific clones to (CBA/J x B10.BR)F1 x B10.BR stimulators. Results of these segregation analyses indicated that the Mls system is composed of at least two independent and unlinked genes which encode, respectively, the determinants identified as Mlsa and Mlsc.