Beryllium binding to HLA-DP molecule carrying the marker of susceptibility to berylliosis glutamate beta 69.
Berylliosis is a chronic granulomatous disorder caused by inhalation of Be dusts that is driven by the accumulation of Be-specific CD4+ Th1-cells at disease sites. Susceptibility to berylliosis has been associated with the supratypic variant of HLA-DP gene coding for glutamate at position beta69 (HLA-DPbetaGlu69). The aim of this study was to test the hypothesis that the HLA-DPbetaGlu69 residue plays a role in the interaction with Be. To this end, soluble HLA-DP2 molecule (carrying betaGlu69) and its mutated form carrying lysine at position beta69 (HLA-DP2Lys69) were produced in Drosophila melanogaster and then used in a Be binding assays. BeSO4 (1-1000 microM) was used to compete for the binding of the biotinilated invariant chain-derived peptide CLIP (50 microM). BeSO4 was capable of compete out biotin-CLIP binding from the HLA-DP2 (IC50%: 4.5 microM of BeSO4 at pH 5.0 and 5.5 microM of BeSO4 at pH 7.5), but not from the HLA-DP2Lys69 molecule (IC50%: 480 microM of BeSO4 at pH 5.0 and 220 microM of BeSO4 at pH 7.5). Moreover, the binding of NFLD.M60, a MoAb recognizing an epitope in the HLA-DP peptide binding region, to the HLA-DP2, but not to the HLA-DP2Lys69 soluble molecules was inhibited BeSO4. NFLD.M60 binding to HLA-DP2, but not to HLA-DP2Lys69 stably transfected murine cells was also inhibited by Be both at pH 5.0 and at pH 7.5. The data indicate a direct interaction of Be with the HLA-DPGlu69 molecule, in the absence of antigen processing.
Amicosante
M
M
Laboratory of Clinical Pathology, I.R.C.C.S. L. Spallanzani, Rome, Italy. massimo.amicosante@uniroma2.it
Sanarico
N
N
Berretta
F
F
Arroyo
J
J
Lombardi
G
G
Lechler
R
R
Colizzi
V
V
Saltini
C
C
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics / Q000276:immunology; D000818:Animals; D001607:Berylliosis / Q000235:genetics / Q000276:immunology*; D001608:Beryllium / Q000276:immunology* / Q000378:metabolism*; D015415:Biomarkers; D002460:Cell Line; D004331:Drosophila melanogaster / Q000235:genetics; D020022:Genetic Predisposition to Disease; D005822:Genetic Vectors; D018698:Glutamic Acid / Q000235:genetics* / Q000378:metabolism; D006682:HLA-DP Antigens / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding / Q000276:immunology; D012995:Solubility
D015415:Biomarkers; D006682:HLA-DP Antigens; D018698:Glutamic Acid; D008239:Lysine; D001608:Beryllium