Atemezem Aurélie, Mbemba Elisabeth, Marfaing Renée, Vaysse Jenny, Pontet Michel, Saffar Line, Charnaux Nathalie, Gattegno Liliane
UPRES 3410, Biothérapies, Bénéfices et Risques, UFR-SMBH, Université Paris XIII, Bobigny et Hôpital Jean Verdier, Bondy 93017, France.
Biochem Biophys Res Commun. 2002 Aug 23;296(3):507-14. doi: 10.1016/s0006-291x(02)00909-9.
We have previously reported that alpha-fetoprotein (AFP) inhibits infection of human monocyte-derived macrophages (MDM) by R5-HIV-1 strains and that a peptide mimicking the clade B HIV-1 gp120 consensus V3 domain (V3Cs) binds to CCR5. We demonstrate here that AFP binds high- and low-affinity binding sites of MDM, characterized, respectively, by 5.15 and 100nM K(d) values. Heat denaturation or neuraminidase treatment of AFP inhibits this binding, suggesting the involvement of protein-protein and lectin-carbohydrate interactions. Moreover, AFP displaces V3Cs binding to MDM. In addition, MIP-1beta, the most specific CCR5 ligand, displaces AFP binding to MDM (IC(50)=4.3nM). Finally, we demonstrate that AFP binds to a ligand of HIV-gp120 V3Cs domain, CCR5, expressed by MDM and by HeLa cells expressing CCR5. Such binding is not observed in the presence of HeLa cells lacking CCR5. The present results provide strong evidence that AFP directly binds to CCR5 expressed by human primary macrophages and by transfected CCR5+ HeLa cells.
我们之前曾报道，甲胎蛋白（AFP）可抑制R5型HIV-1毒株对人单核细胞衍生巨噬细胞（MDM）的感染，且一种模拟B亚型HIV-1 gp120共有V3结构域（V3Cs）的肽可与CCR5结合。我们在此证明，AFP可结合MDM的高亲和力和低亲和力结合位点，其解离常数（K(d)）值分别为5.15和100nM。对AFP进行热变性或神经氨酸酶处理可抑制这种结合，提示存在蛋白质-蛋白质和凝集素-碳水化合物相互作用。此外，AFP可取代与MDM结合的V3Cs。另外，最特异性的CCR5配体MIP-1β可取代与MDM结合的AFP（半数抑制浓度（IC(50)）=4.3nM）。最后，我们证明AFP可与MDM以及表达CCR5的HeLa细胞所表达的HIV-gp120 V3Cs结构域的配体CCR5结合。在缺乏CCR5的HeLa细胞存在时未观察到这种结合。目前的结果提供了有力证据，表明AFP可直接与人原代巨噬细胞以及转染的CCR5+ HeLa细胞所表达的CCR5结合。
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