Generation and characterization of a bivalent protein boost for future clinical trials: HIV-1 subtypes CR01_AE and B gp120 antigens with a potent adjuvant

PLoS One. 2018 Apr 26;13(4):e0194266. doi: 10.1371/journal.pone.0194266. eCollection 2018.

Abstract

The RV144 Phase III clinical trial with ALVAC-HIV prime and AIDSVAX B/E subtypes CRF01_AE (A244) and B (MN) gp120 boost vaccine regime in Thailand provided a foundation for the future development of improved vaccine strategies that may afford protection against the human immunodeficiency virus type 1 (HIV-1). Results from this trial showed that immune responses directed against specific regions V1V2 of the viral envelope (Env) glycoprotein gp120 of HIV-1, were inversely correlated to the risk of HIV-1 infection. Due to the low production of gp120 proteins in CHO cells (2-20 mg/L), cleavage sites in V1V2 loops (A244) and V3 loop (MN) causing heterogeneous antigen products, it was an urgent need to generate CHO cells harboring A244 gp120 with high production yields and an additional, homogenous and uncleaved subtype B gp120 protein to replace MN used in RV144 for the future clinical trials. Here we describe the generation of Chinese Hamster Ovary (CHO) cell lines stably expressing vaccine HIV-1 Env antigens for these purposes: one expressing an HIV-1 subtype CRF01_AE A244 Env gp120 protein (A244.AE) and one expressing an HIV-1 subtype B 6240 Env gp120 protein (6240.B) suitable for possible future manufacturing of Phase I clinical trial materials with cell culture expression levels of over 100 mg/L. The antigenic profiles of the molecules were elucidated by comprehensive approaches including analysis with a panel of well-characterized monoclonal antibodies recognizing critical epitopes using Biacore and ELISA, and glycosylation analysis by mass spectrometry, which confirmed previously identified glycosylation sites and revealed unknown sites of O-linked and N-linked glycosylations at non-consensus motifs. Overall, the vaccines given with MF59 adjuvant induced higher and more rapid antibody (Ab) responses as well as higher Ab avidity than groups given with aluminum hydroxide. Also, bivalent proteins (A244.AE and 6240.B) formulated with MF59 elicited distinct V2-specific Abs to the epitope previously shown to correlate with decreased risk of HIV-1 infection in the RV144 trial. All together, these results provide critical information allowing the consideration of these candidate gp120 proteins for future clinical evaluations in combination with a potent adjuvant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines / immunology
  • Adjuvants, Immunologic*
  • Animals
  • Antibodies, Neutralizing / immunology
  • Antigen-Antibody Reactions
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Epitopes / immunology
  • Female
  • Glycosylation
  • Guinea Pigs
  • HIV Antibodies / blood
  • HIV Antibodies / immunology
  • HIV Antibodies / metabolism
  • HIV Antigens / genetics
  • HIV Antigens / immunology*
  • HIV Antigens / metabolism
  • HIV Envelope Protein gp120 / genetics
  • HIV Envelope Protein gp120 / immunology*
  • HIV Envelope Protein gp120 / metabolism
  • HIV Infections / prevention & control
  • HIV-1 / immunology
  • HIV-1 / metabolism
  • Humans
  • Polysorbates
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / immunology
  • Recombinant Proteins / isolation & purification
  • Squalene / immunology

Substances

  • AIDS Vaccines
  • AIDSVAX
  • Adjuvants, Immunologic
  • Antibodies, Neutralizing
  • Epitopes
  • HIV Antibodies
  • HIV Antigens
  • HIV Envelope Protein gp120
  • MF59 oil emulsion
  • Polysorbates
  • Recombinant Proteins
  • gp120 protein, Human immunodeficiency virus 1
  • Squalene

Grants and funding

This work was supported by Global Health Grant OPP1017604 to GSK and SWB and the Collaboration for AIDS Vaccine Discovery grants OPP1032144 (to Duke University and DCM) and OPP1151646 (to Fred Hutchison Cancer Research Center and RG) from the Bill & Melinda Gates Foundation (BMGF). The funders did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section below. HVT was partially supported by a grant from the Swiss National Science Foundation (P3SMP3_148406/1). The work performed at MHRP was supported by a cooperative agreement (W81XWH-11-2-0174) and (W81XWH-07-2-0067 to NLM) between the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., and the U.S. Department of Defense. This work was sponsored by GlaxoSmithKline Biologicals SA, which was involved in all stages of the study conduct and analysis.