title: Stabilization of a soluble, native-like trimeric form of an efficiently cleaved Indian HIV-1 clade C envelope glycoprotein.
abstract: Designing an effective HIV-1 envelope glycoprotein (Env) immunogen for elicitation of broadly neutralizing antibodies (bNAbs) is a challenging task because of the high sequence diversity, heavy glycosylation, and inherent meta-stability of Env. Based on the antigenic profile of recently isolated bNAbs, the rational approach to immunogen design is to make a stable version of the Env trimer, which mimics the native trimeric Env present on the viral surface. The SOSIP.664 form of a clade A Env, BG505, yields a homogeneous and well ordered prefusion trimeric form, which maintains structural integrity and desired antigenicity. Following the same approach, we attempted to stabilize a naturally occurring efficiently cleaved clade C Env, namely 4-2.J41, isolated from an Indian patient. Although the SOSIP form of 4-2.J41 failed to produce reasonably well ordered trimers, the 4-2.J41.SOSIP.664 Env could be stabilized in a native-like trimeric form by swapping a domain from BG505 Env to 4-2.J41 Env. Using various biochemical and biophysical means we confirmed that this engineered Env is cleaved, trimeric, and it retains its native-like quaternary conformation exposing mostly broadly neutralizing epitopes. Moreover, introduction of a disulfide bond in the bridging sheet region further stabilized the closed conformation of the Env. Thus, our 4-2.J41.SOSIP.664 Env adds to the increasing pool of potential immunogens for a HIV-1 vaccine, particularly for clade C, which is the most prevalent in India and many other countries. Besides, the approach used to stabilize the 4-2.J41 Env may be used successfully with Envs from other HIV-1 strains as well. Additionally, a soluble native trimeric form of an efficiently cleaved membrane-bound Env, 4-2.J41, may be beneficial for immunization studies using various prime-boost strategies.
authors.affiliation: HIV Vaccine Translational Research Laboratory, Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India. Electronic address: sahmed@thsti.res.in.
authors.forename: Shubbir
authors.initials: S
authors.lastname: Ahmed
authors.affiliation: HIV Vaccine Translational Research Laboratory, Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India.
authors.forename: Tripti
authors.initials: T
authors.lastname: Shrivastava
authors.affiliation: HIV Vaccine Translational Research Laboratory, Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India.
authors.forename: Naresh
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery The Scripps Research Institute, La Jolla, California 92037.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Ozorowski
authors.affiliation: Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery The Scripps Research Institute, La Jolla, California 92037.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Ward
authors.affiliation: HIV Vaccine Translational Research Laboratory, Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India; International AIDS Vaccine Initiative, New York, New York 10004. Electronic address: bchakrabarti@iavi.org.
authors.forename: Bimal K
authors.initials: BK
authors.lastname: Chakrabarti
mesh_terms: D016915:AIDS Vaccines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D015497:HIV-1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D000072417:Protein Domains; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D054299:env Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D016915:AIDS Vaccines; D011994:Recombinant Proteins; D054299:env Gene Products, Human Immunodeficiency Virus
keywords: AIDS; human immunodeficiency virus (HIV); protein expression; protein purification; vaccine; vaccine development; viral protein