title: Generation and Characterization of a Bivalent HIV-1 Subtype C gp120 Protein Boost for Proof-of-Concept HIV Vaccine Efficacy Trials in Southern Africa.
abstract: The viral envelope glycoprotein (Env) is the major target for antibody (Ab)-mediated vaccine development against the Human Immunodeficiency Virus type 1 (HIV-1). Although several recombinant Env antigens have been evaluated in clinical trials, only the surface glycoprotein, gp120, (from HIV-1 subtype B, MN, and subtype CRF_01AE, A244) used in the ALVAC prime-AIDSVAX gp120 boost RV144 Phase III HIV vaccine trial was shown to contribute to protective efficacy, although modest and short-lived. Hence, for clinical trials in southern Africa, a bivalent protein boost of HIV-1 subtype C gp120 antigens composed of two complementary gp120s, from the TV1.C (chronic) and 1086.C (transmitted founder) HIV-1 strains, was selected. Stable Chinese Hamster Cell (CHO) cell lines expressing these gp120s were generated, scalable purification methods were developed, and a detailed analytical analysis of the purified proteins was conducted that showed differences and complementarity in the antigenicity, glycan occupancy, and glycan content of the two gp120 molecules. Moreover, mass spectrometry revealed some disulfide heterogeneity in the expressed proteins, particularly in V1V2-C1 region and most prominently in the TV1 gp120 dimers. These dimers not only lacked binding to certain key CD4 binding site (CD4bs) and V1V2 epitope-directed ligands but also elicited reduced Ab responses directed to those epitopes, in contrast to monomeric gp120, following immunization of rabbits. Both monomeric and dimeric gp120s elicited similarly high titer Tier 1 neutralizing Abs as measured in standard virus neutralization assays. These results provide support for clinical evaluations of bivalent preparations of purified monomeric TV1.C and 1086.C gp120 proteins.
authors.affiliation: GSK Vaccines (formerly Novartis Vaccines), 45 Sidney Street, Cambridge, MA, 02139, United States of America.
authors.forename: Carlo
authors.identifier: http://orcid.org/0000-0002-6331-9479
authors.initials: C
authors.lastname: Zambonelli
authors.affiliation: GSK Vaccines (formerly Novartis Vaccines), 45 Sidney Street, Cambridge, MA, 02139, United States of America.
authors.forename: Antu K
authors.initials: AK
authors.lastname: Dey
authors.affiliation: GSK Vaccines (formerly Novartis Vaccines), 45 Sidney Street, Cambridge, MA, 02139, United States of America.
authors.forename: Susan
authors.initials: S
authors.lastname: Hilt
authors.affiliation: GSK Vaccines (formerly Novartis Vaccines), 45 Sidney Street, Cambridge, MA, 02139, United States of America.
authors.forename: Samuel
authors.initials: S
authors.lastname: Stephenson
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, KS, 66047, United States of America.
authors.forename: Eden P
authors.initials: EP
authors.lastname: Go
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, KS, 66047, United States of America.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Clark
authors.affiliation: GSK Vaccines (formerly Novartis Vaccines), 45 Sidney Street, Cambridge, MA, 02139, United States of America.
authors.forename: Mark
authors.initials: M
authors.lastname: Wininger
authors.affiliation: Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Celia
authors.initials: C
authors.lastname: Labranche
authors.affiliation: Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Montefiori
authors.affiliation: Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Hua-Xin
authors.initials: HX
authors.lastname: Liao
authors.affiliation: University of North Carolina, Chapel Hill, NC, United States of America.
authors.forename: Ronald I
authors.initials: RI
authors.lastname: Swanstrom
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, KS, 66047, United States of America.
authors.forename: Heather
authors.initials: H
authors.lastname: Desaire
authors.affiliation: Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Barton F
authors.initials: BF
authors.lastname: Haynes
authors.affiliation: GSK Vaccines (formerly Novartis Vaccines), 45 Sidney Street, Cambridge, MA, 02139, United States of America.
authors.forename: Andrea
authors.initials: A
authors.lastname: Carfi
authors.affiliation: GSK Vaccines (formerly Novartis Vaccines), 45 Sidney Street, Cambridge, MA, 02139, United States of America.
authors.forename: Susan W
authors.initials: SW
authors.lastname: Barnett
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology*; D000353:Africa, Southern; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D016466:CHO Cells; D002986:Clinical Trials as Topic; D006224:Cricetinae; D003412:Cricetulus; D004220:Disulfides / Q000378:metabolism; D000939:Epitopes / Q000276:immunology; D005260:Female; D006031:Glycosylation; D015488:HIV Antigens / Q000276:immunology; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D015658:HIV Infections / Q000097:blood / Q000276:immunology / Q000821:virology; D006679:HIV Seropositivity / Q000276:immunology / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007106:Immune Sera; D055503:Protein Multimerization; D011817:Rabbits; D016896:Treatment Outcome
chemical_list: D016915:AIDS Vaccines; D000911:Antibodies, Monoclonal; D004220:Disulfides; D000939:Epitopes; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; D007106:Immune Sera