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Immunochemical variants of HLA-B27
Journal of Immunology (Baltimore, Md. : 1950)
|March 1, 1983
Summary
Researchers discovered molecular differences within the HLA-B27 antigen, suggesting subtypes previously unrecognized. This finding could impact understanding of spondyloarthropathies associated with HLA-B27.
Area of Science:
- Immunogenetics
- Molecular immunology
Background:
- The human leukocyte antigen HLA-B27 is strongly associated with spondyloarthropathies.
- Previous studies suggested HLA-B27 homogeneity, but monoclonal antibody B27M2 indicated potential heterogeneity.
Purpose of the Study:
- To molecularly define and confirm the heterogeneity of HLA-B27 suggested by B27M2 antibody reactivity.
- To differentiate HLA-B27 variants using advanced molecular techniques.
Main Methods:
- Preparation of detergent extracts from B cell lines with differential B27M2 reactivity.
- Immunoprecipitation using specific allogeneic or monoclonal antibodies.
- Analysis via two-dimensional polyacrylamide gel electrophoresis (2D-PAGE).
Main Results:
- HLA-B27 variants reactive (B27M2+) and unreactive (B27M2-) with B27M2 showed distinct isoelectric points (pI) on 2D-PAGE.
- These variants were distinguishable from each other and from the control alloantigen Bw44.
- Tunicamycin treatment (glycosylation blockade) affected molecular weight but not pI, indicating post-translational modifications are not the primary source of pI difference.
Conclusions:
- HLA-B27 antigens exhibit molecular heterogeneity, allowing subdivision into distinct subsets.
- This molecular heterogeneity may have implications for understanding the pathogenesis of HLA-B27-associated diseases, though the exact effects remain unknown.