Well-Ordered Trimeric HIV-1 Subtype B and C Soluble Spike Mimetics Generated by Negative Selection Display Native-like Properties

PLoS Pathogens

Karen Tran¹  Natalia de Val²  Andrew B. Ward³  Javier Guenaga³  Karen Satchwell³  Yu Feng³  Richard T. Wyatt³ 

[1] Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, United States of America;Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America;IAVI Neutralizing Antibody Center at The Scripps Research Institute, La Jolla, California, United States of America

关键词: HIV-1;    Antibodies;    HIV;    Oligomers;    Antigens;    Dimers (Chemical physics);    Melting;    Glycoproteins;   

DOI  :  10.1371/journal.ppat.1004570

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The structure of BG505 gp140 SOSIP, a soluble mimic of the native HIV-1 envelope glycoprotein (Env), marks the beginning of new era in Env structure-based immunogen design. Displaying a well-ordered quaternary structure, these subtype A-derived trimers display an excellent antigenic profile, discriminating recognition by broadly neutralizing antibodies (bNAbs) from non-broadly neutralizing antibodies (non-bNAbs), and provide a solid Env-based immunogenic platform starting point. Even with this important advance, obtaining homogeneous well-ordered soluble SOSIP trimers derived from other subtypes remains challenging. Here, we report the “rescue” of homogeneous well-ordered subtype B and C SOSIP trimers from a heterogeneous Env mixture using CD4 binding site-directed (CD4bs) non-bNAbs in a negative-selection purification process. These non-bNAbs recognize the primary receptor CD4bs only on disordered trimers but not on the native Env spike or well-ordered soluble trimers due to steric hindrance. Following negative selection to remove disordered oligomers, we demonstrated recovery of well-ordered, homogeneous trimers by electron microscopy (EM). We obtained 3D EM reconstructions of unliganded trimers, as well as in complex with sCD4, a panel of CD4bs-directed bNAbs, and the cleavage-dependent, trimer-specific bNAb, PGT151. Using bio-layer light interferometry (BLI) we demonstrated that the well-ordered trimers were efficiently recognized by bNAbs and poorly recognized by non-bNAbs, representing soluble mimics of the native viral spike. Biophysical characterization was consistent with the thermostability of a homogeneous species that could be further stabilized by specific bNAbs. This study revealed that Env trimers generate different frequencies of well-ordered versus disordered aberrant trimers even when they are genetically identical. By negatively selecting the native-like well-ordered trimers, we establish a new means to obtain soluble Env mimetics derived from subtypes B and C for expanded use as candidate vaccine immunogens.

【 授权许可】

CC BY