Takeda A, Ennis F A
Department of Medicine, University of Massachusetts Medical School, Worcester 01655.
AIDS Res Hum Retroviruses. 1990 Aug;6(8):999-1004. doi: 10.1089/aid.1990.6.999.
Although CD4 is a major receptor for human immunodeficiency virus (HIV) infection of cells, studied by ourselves and others clearly show that the Fc receptor (FcR) also plays a role in infection, perhaps in conjunction with other surface receptors. IgG antibodies to HIV-1 will enhance infectivity in cells (such as monocyte-macrophages) that have surface Fc receptors; F(ab')2 fragments of antibodies did not enhance, and blocking of FcR inhibited enhancement. The high-affinity FcR for IgG (Fc gamma RI) appeared to be functional. Sera from HIV-1-infected patients had neutralizing activity at high concentrations, but enhanced infection at low concentrations (i.e., high dilutions). Our studies show that the CD4 receptor is required for antibody-mediated enhancement of infection, as enhancement can be blocked by recombinant soluble CD4 and by Leu3 antibody. Although enhancement can be demonstrated in vitro, the in vivo importance of enhancing antibodies remains to be defined in HIV-1 infection.
虽然CD4是人类免疫缺陷病毒（HIV）感染细胞的主要受体，但我们自己以及其他人的研究清楚地表明，Fc受体（FcR）在感染中也发挥作用，可能是与其他表面受体共同作用。针对HIV-1的IgG抗体可增强具有表面Fc受体的细胞（如单核细胞-巨噬细胞）的感染性；抗体的F(ab')2片段则无增强作用，而阻断FcR可抑制这种增强作用。针对IgG的高亲和力FcR（FcγRI）似乎具有功能。来自HIV-1感染患者的血清在高浓度时有中和活性，但在低浓度（即高稀释度）时会增强感染。我们的研究表明，抗体介导的感染增强需要CD4受体，因为重组可溶性CD4和Leu3抗体可阻断这种增强作用。虽然在体外可证明存在增强作用，但在HIV-1感染中，增强性抗体在体内的重要性仍有待确定。
