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

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.

Glycan Profiles of gp120 Protein Vaccines from Four Major HIV-1 Subtypes Produced from Different Host Cell Lines under Non-GMP or GMP Conditions

“…Diverse purification processes are used both in the lab and during clinical-grade protein purification, such as antibody-based affinity columns, size-exclusion chromatography, lectin-based columns, or the industry preferred ion-exchange columns. Recently, a few recombinant GMP-grade Env-based vaccines have been characterized by analysis of glycans (14,15) but the number of Env proteins included in those studies was limited and they did not provide direct comparison between different cell lines or between GMP and non-GMP for the production of the same Env proteins.…”

Robotic selection for the rapid development of stable CHO cell lines for HIV vaccine production

“…Efforts to produce HIV Env proteins for clinical testing have been complicated by problems of poor expression, heterogeneity in N-linked glycosylation and net charge, and low yields from downstream purification [ 36 , 46 , 48 – 56 ]. To address these problems we combined a high efficiency electroporation device (MaxCyte STX, MaxCyte Inc., Gaithersburg, MD), a robotic cell selection system, ClonePix2 (Molecular Devices, Sunnyvale, CA) and a novel cell line (MGAT1 - CHO 3.4F10) that was recently developed in our lab [ 57 ].…”

Impact of T h 1 CD4 Follicular Helper T Cell Skewing on Antibody Responses to an HIV-1 Vaccine in Rhesus Macaques

“…D IP-10 Protein ALFQ vaccine elicits high avidity anti-Env antibody with ADCC and ADP activities. Next, we quantified avidity of IgG binding antibodies (as disassociation constants, kd) in sera collected at 2 weeks post final DNA prime and after each of the protein boosts using Surface Plasmon Resonance (SPR) to C.1086 gp140 protein (23). The data showed that gp140-specific antibodies reached higher avidity with each sequential immunization in both vaccine groups (p < 0.0001, Figure 3A, (Figure 2), SPR-based IgG measurements, expressed as relative units, showed significantly higher gp140 IgG in the D IP-10 P ALFQ vaccine group (p< 0.0001, Figure 3C).…”

“…mM NaCl pH 7.4 using a standard amine coupling kit, as previously described(23,67). The CM5-S serieschip surface was activated with a 1:1 mixture of 0.4 M 1-ethyl-3-(3-dimethylaminopropyl) carbodimide hydrochloride (EDC) and 0.1 M N-hydroxysuccinimide (NHS) for 600 s (GE Healthcare).…”