Cell-surface expression and immune receptor recognition of HLA-B27 homodimers.
OBJECTIVE
HLA-B27 is capable of forming in vitro a heavy-chain homodimer structure lacking beta(2)-microglobulin. We undertook this study to ascertain if patients with spondylarthritis express beta(2)-microglobulin-free HLA-B27 heavy chains in the form of homodimers and receptors for HLA-B27 homodimers.


METHODS
Expression of HLA-B27 heavy chains by mononuclear cells was analyzed by fluorescence-activated cell sorter staining, Western blotting with the monoclonal antibody HC-10, and 2-dimensional isoelectric focusing. Fluorescence-labeled tetrameric complexes of HLA-B27 heavy-chain homodimers were constructed in which each dimer comprised one His-tagged heavy chain and one biotinylated heavy chain, and were used to stain patient and control mononuclear cells and transfected cell lines.


RESULTS
Patients with spondylarthritis expressed cell-surface HLA-B27 homodimers. Populations of synovial and peripheral blood monocytes, and B and T lymphocytes from patients with spondylarthritis, and controls carried receptors for HLA-B27 homodimers. Experiments with transfected cell lines demonstrated that KIR3DL1 and KIR3DL2, and immunoglobulin-like transcript 4 (ILT4), but not ILT2, are receptors for HLA-B27 homodimers.


CONCLUSIONS
Patients with spondylarthritis express both HLA-B27 heavy-chain homodimers and receptors for HLA-B27 homodimers. This may be of significance with regard to disease pathogenesis.
Kollnberger
Simon
S
Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
Bird
Lucy
L
Sun
Mei-Yi
MY
Retiere
Christelle
C
Braud
Veronique M
VM
McMichael
Andrew
A
Bowness
Paul
P
D000328:Adult; D000954:Antigens, Surface / Q000737:chemistry / Q000276:immunology*; D019281:Dimerization; D005260:Female; D015796:HLA-B27 Antigen / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D009000:Monocytes / Q000276:immunology; D011971:Receptors, Immunologic / Q000032:analysis / Q000276:immunology*; D025241:Spondylarthritis / Q000276:immunology*; D013582:Synovial Fluid / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology
D000954:Antigens, Surface; D015796:HLA-B27 Antigen; D011971:Receptors, Immunologic