Expression of the W6/32 HLA epitope by cells of rat, mouse, human and other species: critical dependence on the interaction of specific MHC heavy chains with human or bovine β2-microglobulin
✍ Scribed by Wilfred A. Jefferies; G. Gordon MacPherson
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- English
- Weight
- 851 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
The HLA class I epitope W6132 is conformationally dependent on both heavy chain and P2-microglobulin (P2M). Previously, the W6l32 epitope has been detected in humans and other primates as well as from bovine sources. Two controversial reports suggest the W6/32 epitope is constitutively expressed by either normal or transformed murine cells expressing the Db allele. Here we show that the appearance of the W6/32 epitope in murine cells results from the association of either the Db or Kd gene products with either bovine or human P2M. We use congenic mouse strains and hybrid H-2 class I genes between Db and Kb to map the W6132 epitope to particular amino acid residues in the a2 domain. Subsequently, we show that PzM exchange is not confined to murine or human cells in vitro but can be detected after P2M injection into a mouse. The data presented suggests that f32M exchange takes place at the cell surface under physiological conditions and indicates that MHC class I heavy chains are in an equilibrium between the bound and unbound form of P2M.