PDF(Pubmed)
Abstract：
Broadly neutralizing antibodies are proposed as therapeutic and prophylactic agents against HIV-1, but their potency and breadth are less than optimal. This study describes the immunization of a llama with the prefusion-stabilized HIV-1 envelope (Env) trimer, BG505 DS-SOSIP, and the identification and improvement of potent neutralizing nanobodies recognizing the CD4-binding site (CD4bs) of vulnerability. Two of the vaccine-elicited CD4bs-targeting nanobodies, G36 and R27, when engineered into a triple tandem format with llama IgG2a-hinge region and human IgG1-constant region (G36×3-IgG2a and R27×3-IgG2a), neutralized 96% of a multiclade 208-strain panel at geometric mean IC80s of 0.314 and 0.033 µg mL-1, respectively. Cryo-EM structures of these nanobodies in complex with Env trimer revealed the two nanobodies to neutralize HIV-1 by mimicking the recognition of the CD4 receptor. To enhance their neutralizing potency and breadth, nanobodies are linked to the light chain of the V2-apex-targeting broadly neutralizing antibody, CAP256V2LS. The resultant human-llama bispecific antibody CAP256L-R27×3LS exhibited ultrapotent neutralization and breadth exceeding other published HIV-1 broadly neutralizing antibodies, with pharmacokinetics determined in FcRn-Fc mice similar to the parent CAP256V2LS. Vaccine-elicited llama nanobodies, when combined with V2-apex broadly neutralizing antibodies, may therefore be able to fulfill anti-HIV-1 therapeutic and prophylactic clinical goals.
摘要：
广泛的中和抗体被提出作为抗HIV-1的治疗剂和预防剂,但是它们的效力和宽度不是最佳的。这项研究描述了用融合前稳定的HIV-1包膜（Env）三聚体免疫美洲驼，BG505DS-SOSIP,以及识别和改进识别脆弱性的CD4结合位点（CD4bs）的有效中和纳米抗体。两种疫苗引发的CD4bs靶向纳米抗体，G36和R27，当工程化为具有美洲驼IgG2a铰链区和人IgG1恒定区（G36×3-IgG2a和R27×3-IgG2a）的三重串联形式时，中和了96％的多分支208应变面板，几何平均IC50分别为0.314和0.033µgmL-1。与Env三聚体复合的这些纳米抗体的Cryo-EM结构揭示了两个纳米抗体通过模拟对CD4受体的识别来中和HIV-1。为了增强它们的中和效力和广度，纳米抗体连接到V2-apex靶向广泛中和抗体的轻链，CAP256V2LS。所得的人美洲驼双特异性抗体CAP256L-R27×3LS表现出超强力中和和宽度超过其他公开的HIV-1广泛中和抗体，在FcRn-Fc小鼠中测定的药代动力学类似于亲本CAP256V2LS。疫苗引发的美洲驼纳米抗体，当与V2-apex广泛中和抗体结合时，因此可能能够实现抗HIV-1治疗性和预防性临床目标。
