Abe R, Ryan J J, Hodes R J
Immunology Branch, National Cancer Institute, Bethesda, Maryland 20892.
J Exp Med. 1987 Oct 1;166(4):1150-5. doi: 10.1084/jem.166.4.1150.
Mls determinants share with MHC products the unique property of stimulating T cells at extraordinarily high precursor frequencies. The Mls system was originally described as a single locus on chromosome 1, with four alleles, Mlsa, Mlsb, Mlsc, and Mlsd, that encode polymorphic cell surface structures. However, the fundamental issues of polymorphism and allelism in the Mls system remain controversial. To clarify these questions, a formal segregation analysis of the genes encoding Mlsa and Mlsc determinants was carried out by testing the capacity of spleen cells from progeny of (Mlsa X Mlsc)F1 X Mlsb breedings to stimulate responses by unprimed T cells and by Mlsa- and Mlsc-specific cloned T cells. The results of this analysis indicated that the gene encoding Mlsa determinants is neither allelic to nor linked to the gene encoding Mlsc determinants. Together with previous findings, these results also suggest that another strongly stimulatory type, Mlsd, in fact results from the independent expression of unlinked Mlsa and Mlsc gene products. Based on these observations, it is concluded that, contrary to conventional concepts, the stimulatory phenotypes designated as Mlsa, Mlsc, and Mlsd can be accounted for by the independent expression of the products of at least two unlinked gene loci.
Mls决定簇与MHC产物具有共同特性，即在极高的前体频率下刺激T细胞。Mls系统最初被描述为位于1号染色体上的一个单一位点，有四个等位基因，即Mlsa、Mlsb、Mlsc和Mlsd，它们编码多态性细胞表面结构。然而，Mls系统中多态性和等位性的基本问题仍存在争议。为了阐明这些问题，通过检测（Mlsa×Mlsc）F1与Mlsb杂交后代的脾细胞刺激未致敏T细胞以及Mlsa和Mlsc特异性克隆T细胞反应的能力，对编码Mlsa和Mlsc决定簇的基因进行了正式的分离分析。该分析结果表明，编码Mlsa决定簇的基因既与编码Mlsc决定簇的基因非等位，也不与之连锁。结合先前的研究结果，这些结果还表明，另一种强刺激类型Mlsd实际上是由不连锁的Mlsa和Mlsc基因产物的独立表达所致。基于这些观察结果，得出的结论是，与传统概念相反，被指定为Mlsa、Mlsc和Mlsd的刺激表型可以由至少两个不连锁基因座的产物的独立表达来解释。
