Translation in Xenopus laevis oocytes of hybrid selected LEW rat RT1.B alpha- and beta-chain transcripts results in serologically discrete class II polypeptide chain complexes.
Using the non-crossreactive mAb MRC-OX3 and MRC-OX6, two serologically distinct RT1.B-specific (I-A equivalent) alpha, beta heterodimers have previously been described by us as residing at the cell surface of LEW rat spleen cells. The two-chain elements were suggested to represent stable conformation isomers, diverged by dissociation of the mature gamma-chain from a mAb MRC-OX6 reactive biosynthetic intermediate, composed of terminally glycosylated alpha-, beta- and gamma-chains. In this study we addressed the question of whether or not the presence of terminally glycosylated invariant gamma-chain was obligatory for the formation of the two MRC-OX3 and MRC-OX6 reactive two-chain complexes. The synthesis of RT1.B-specific alpha, beta heterodimers was therefore initiated, in the absence of accompanying invariant gamma-chains, by microinjecting hybrid-selected RT1.B alpha- and beta-specific mRNA into oocytes of Xenopus laevis for translation. Class II molecules produced were analyzed by affinity chromatography of radioactive-labeled oocyte detergent lysates using the appropriate monoclonal immunoadsorbents for identification. Although rat gamma-chain mRNA was excluded in this assay system, distinct MRC-OX3 and MRC-OX6 reactive two-chain complexes were detected by two-dimensional gel electrophoresis. These findings clearly indicate that the formation of the two RT1.B-specific alpha, beta heterodimers is independent of the presence of the rat invariant gamma-chain.
Henkes
W
W
Institute for Immunology, Johannes Gutenberg University, Mainz, F.R.G.
Reske
K
K
D000818:Animals; D000911:Antibodies, Monoclonal; D015342:DNA Probes; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D008297:Male; D009865:Oocytes; D014176:Protein Biosynthesis; D012313:RNA; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D011917:Rats, Inbred Lew; D013154:Spleen / Q000166:cytology; D014982:Xenopus laevis
D000911:Antibodies, Monoclonal; D015342:DNA Probes; D000949:Histocompatibility Antigens Class II; D012333:RNA, Messenger; D012313:RNA