Structure and Function of MHC Class Ib Molecules

除了在主要组织相容性复合体(MHC)内编码的高度多态的I类基因外，哺乳动物的基因组还包含寡核苷酸或单态的I类基因。后一类I类基因，称为Ib类基因，编码新生儿肠道Fc受体(FcRN)，参与免疫球蛋白从母亲到后代的运输；CD1分子，参与糖脂向T细胞的呈递；以及锌-α2-糖蛋白，功能未知。本研究的目的是深入了解Ib类基因的结构、功能和进化。获得的具体结果如下：1)克隆了人和小鼠FcRN分子重链的基因组克隆，并对基因进行了染色体定位。2)我们发现CD1基因被定位的遗传区域与MHC.3是平行的)我们发现小鼠锌-α2-糖蛋白基因定位在MHC.4之外)我们发现人类CD1b分子可能没有结合的多肽。

Besides the class I genes that are highly polymorphic and encoded within the major histocompatibility complex (MHC), the genome of mammals contains class I genes that are oligo- or monomorphic. The latter category of class I genes, known as class Ib genes, encodes the neonatal intestinal Fc receptor (FcRn) involved in the transport of IgG from mother to offspring ; CD1 molecules involved in the presentation of glycolipids to T cells ; and zinc-alpha2-glycoprotein with no known function. The aims of the present study were to gain insights into the structure, function, and evolution of class Ib genes. The specific results obtained are as follows : 1) We cloned the genomic clones coding for the heavy chains of the human and mouse FcRn molecules, and determined the chromosomal localization of the genes. 2) We showed that the genetic region where the CD1 genes have been mapped is paralogous to the MHC.3) We showed that the mouse gene for zinc-alpha2-glycoprotein maps outside the MHC.4) We found that human CD1b molecules probably have no bound peptides.