Cross-reactive HIV-1 neutralizing monoclonal antibodies selected by screening of an immune human phage library against an envelope glycoprotein (gp140) isolated from a patient (R2) with broadly HIV-1 neutralizing antibodies
Cross-reactive HIV-1 neutralizing monoclonal antibodies selected by screening of an immune human phage library against an envelope glycoprotein (gp140) isolated from a patient (R2) with broadly HIV-1 neutralizing antibodies
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DOI：
10.1016/j.virol.2007.01.015
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发表时间：
2007-06-20
期刊：
影响因子：
3.7
通讯作者：
Dimitrov, Dimiter S.
中科院分区：
文献类型：
--
作者：
Choudhry, Vidita;Zhang, Mei-Yun;Dimitrov, Dimiter S.
在HIV感染中激发广泛交叉反应的中和抗体(BcnAbs)是很少见的。为了验证这种抗体可以由具有特殊免疫原性的HIV包膜糖蛋白(Env)诱导产生的假设，并鉴定新的BenAbs，我们使用来自高水平bcnAbs供体(R2)的可溶性env胞外区(GP 140)作为抗原，用于淘洗免疫噬菌体展示的抗体库。与使用来自另外两个分离株(89.6和IIIB)的包膜病毒相比，使用R2包膜病毒产生的交叉反应抗体克隆数量显著增加。已鉴定的两个人类单抗M22和Tn24具有与gp120特异性bcnAbm18和m14相似或相同的序列、中和和结合活性。使用R2 env而不是其他env进行平移导致了一种新的gp41特异性hmAb M46的鉴定。对于几个被测试的HIV-1初级分离株，其摩尔效力与T20相当。它抑制了来自不同分支的初级分离物的进入，并对低CCR5表面浓度的细胞系具有增强的活性。M46对一组C分支分离株的中和活性在基于外周血单核细胞的检测中显著高于基于细胞表面相关CCR5浓度相对较高的细胞系的AIL检测(5个分离株中有4个中和的IC50在1.5至25微克/毫升范围内)。与2175和Z13相反，该抗体不与变性的gp140和gp41衍生的多肽结合，表明其表位的构象性质。它与5-螺旋束结合，但不与N-七重复螺旋卷曲和6-螺旋束结构结合，表明gp41七重复对其表位的贡献和可能的中和机制。这些结果表明，R2 env可能含有独特的暴露保守表位，这可能有助于其在动物和人类中诱导广泛的交叉反应抗体；新发现的抗体可能有助于开发新的疫苗免疫原和治疗方法。(C)2007 Elsevier Inc.保留所有权利。
Elicitation of broadly cross-reactive neutralizing antibodies (bcnAbs) in HIV infections is rare. To test the hypothesis that such antibodies could be elicited by HIV envelope glycoproteins (Envs) with unusual immunogenic properties and to identify novel benAbs, we used a soluble Env ectodomain (gp 140) froin a donor (R2) with high level of bcnAbs as an antigen for panning of an immune phage-displayed antibody library. The panning with the R2 Env resulted in significantly higher number of cross-reactive antibody clones than by using Envs from two other isolates (89.6 and IIIB). Two of the identified human monoclonal antibodies (hmAbs), m22 and tn24, had sequences, neutralizing and binding activities similar or identical to those of the gp120-specific bcnAbs m 18 and m 14. The use of the R2 Env but not other Envs for panning resulted in the identification of a novel gp41-specific hmAb, m46. For several of the tested HIV-1 primary isolates its potency on molar basis was comparable to that of T20. It inhibited entry of primary isolates from different clades with an increased activity for cell lines with low CCR5 surface concentrations. The m46 neutralizing activity against a panel of clade C isolates was significantly higher in an assay based on peripheral blood mononuclear cells (4 out of 5 isolates were neutralized with an IC50 in the range from 1.5 to 25 mu g/ml) than in ail assay based on a cell line with relatively high concentration of cell-surface-associated CCR5. In contrast to 2175 and Z13, this antibody did not bind to denatured gp140 and gp41-derived peptides indicating a conformational nature of its epitope. It bound to a 5-helix bundle but not to N-heptad repeat coiled coils and a 6-helix bundle construct indicating contribution of both gp41 heptad repeats to its epitope and to a possible mechanism of neutralization. These results indicate that the R2 Env may contain unique exposed conserved epitopes that could contribute to its ability to elicit broadly cross-reactive antibodies in animals and humans; the newly identified antibodies may help in the development of novel vaccine immunogens and therapeutics. (C) 2007 Elsevier Inc. All rights reserved.