Glimcher L H, Polla B S, Poljak A, Morton C C, McKean D J
J Immunol. 1987 Mar 1;138(5):1519-23.
Polymorphic class II (Ia) major histocompatibility complex (MHC) gene products associate intracytoplasmically with a third nonpolymorphic class II molecule, the invariant chain (Ii), which is encoded by gene(s) unlinked to the MHC. Although the role of the Ii chain in the expression of cell surface Ia molecules is unclear, it has been suggested that the Ii chain helps in the assembly and intracellular transport of class II antigens. In this study, we demonstrate that the murine polymorphic class II antigens of an interspecies mouse-human hybrid, which has segregated the murine invariant chain gene, associates with the human invariant chain gene intracytoplasmically. The murine Ia antigens are expressed on the cell surface and can function as restriction elements in antigen presentation to T cells. The biochemical analysis demonstrates that the regions of the Ii gene that are critical to its interaction with Ia molecules are conserved between species.
多态性II类（Ia）主要组织相容性复合体（MHC）基因产物在细胞质内与第三种非多态性II类分子恒定链（Ii）缔合，恒定链由与MHC不连锁的基因编码。虽然Ii链在细胞表面Ia分子表达中的作用尚不清楚，但有人提出Ii链有助于II类抗原的组装和细胞内运输。在本研究中，我们证明了已分离出鼠恒定链基因的种间小鼠 - 人杂交体的鼠多态性II类抗原在细胞质内与人恒定链基因缔合。鼠Ia抗原在细胞表面表达，并可作为抗原呈递给T细胞的限制元件发挥作用。生化分析表明，Ii基因中对其与Ia分子相互作用至关重要的区域在物种间是保守的。
