A novel β2-microglobulin (β2m) deficient kidney carcinoma cell line, KJ29, has been selected to assess the influence of β2m on the intracellular accumulation and post-translational modifications of HLA-A, -B, -C molecules. HLA-A2, -B27, -CW1 molecules synthesized by KJ29 cells have been compared to heavy chains synthesized in transfectants expressing a large stoichiometric excess of β2m. We show that HLA-A2 and - B27 free heavy chains are unstable in absence of β2m, and capable of nearly complete assembly in β2m transfectants. At variance, HLA-CW1 heavy chains are relatively stable, and their assembly with β2m is largely incomplete both in the presence and the absence of β2m. Free HLA-B27 heavy chains display, in β2m defective cells, an altered molecular weight and a low or absent sialilation, suggesting an altered biosynthesis and intracellular transport. At variance, HLA-CW1 heavychain components are neuraminidase insensitive. No changes are apparent in either the molecular weight or the net charge of HLA-CW1 upon transfection with β2m. These results demonstrate distinctive biochemical properties of HLA-C molecules, and suggest that at least HLA-CW1, and, possibly, other alleles at the HLA-C locus, might be relatively refractory to those defects in the assembly of class I molecules which impair their intracellular traffic.
|Number of pages||5|
|Publication status||Published - Sep 1996|
- Free heavy chains
- HLA-C antigens
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology