Generation and Characterization of an HIV-1 Subtype C Transmitted and Early Founder Virus Consensus Sequence

Abstract

The tight bottleneck during HIV-1 transmission generally results in only a single virus variant being transmitted. Investigation of the HIV-1 envelope glycoprotein (Env) can identify vulnerabilities of transmitting viruses that can be targeted by vaccines designed to elicit protection against global HIV-1. This study generated an HIV-1 subtype C consensus transmitted and early founder virus Env (EnvFVC) after detailed sequence analysis of 1,894 env genes obtained from 80 acutely infected individuals from South Africa, Malawi, and Zambia. The inferred EnvFVC sequence incorporates characteristics of transmitted and early founder viruses and results in the expression of a functional and conformationally intact Env. Overall, the "subtype-based" or "region-based" EnvFVC described here can be used in the development of a useful immunogen for novel vaccine design.

Immunization with HIV-1 trimeric SOSIP.664 BG505 or founder virus C (FVCEnv) covalently complexed to two-domain CD4S60C elicits cross-clade neutralizing antibodies in New Zealand white rabbits

“…The BG505 SOSIP.664 modifications [9] were introduced in the original FVC ENV sequence [19] to produce the FVC ENV SOSIP.664 gp140 protein. The changes included the A501C and T605C mutations to create the interprotomer SOS disulphide link, the I559P mutation to stabilize the trimer, the replacement of the R517, E518, K519, R520 to to 6×Arg (R517-R522) for the furin cleavage site, and finally the sequence truncation after the Asp at position 664 to delete the MPER region of gp41 and to enhance the solubility of the protein ( Supplementary Fig.…”

“…An Asn at position 332 and a Ser at position 334, the potential N -linked glycosylation site on which certain V3-directed antibodies are highly dependent, was already present in the FVC ENV sequence. Comparatively, the FVC ENV sequence, which is a consensus envelope of subtype C founder viruses [19] , contained shorter V1V2 and V4 loops ( Supplementary Fig. S1 ).…”

“…The BG505 SOSIP.664 clone in the VRC3831 plasmid was kindly provided by Dr. Peter Kwong. The subtype C derived FVC env gene constructed from the consensus sequence of TF viruses [19] was used to incorporate the SOSIP.664 mutations: I559P, A501C, T605C, 508 REKR 511 to R6, and MPER truncation at residue 664 [7] , [8] . The codon-optimized FVC ENV SOSIP.664 clone was synthesized by GeneArt (Life Technologies, Regensburg, Germany) and cloned into the pCDNA3.3 expression vector (Invitrogen, Grand Island, NY).…”

“…Previous work using an Env immunogen composed of the consensus sequence obtained from over 1,800 subtype C TF envelopes [19] ; namely, the Founder Virus C Env (FVC ENV ), covalently complexed to the first two domains of CD4 (2dCD4) via cysteine linkage through targeted intermolecular binding of gp120 to CD4 by introduction of a serine to cysteine substitution in CD4 [20] (2dCD4 S60C ) gave rise to exceptional immunogens [21] . The former study made use of various Env conformations, from monomeric to leucine-zipper linked gp140 trimers, with the same outcome: all consistently elicited potent, cross-neutralizing antibody activity against clinically-relevant HIV-1 isolates in New Zealand white rabbits [21] and rhesus macaques (Pereira et al .…”

Engineering and characterising a novel, highly potent bispecific antibody iMab-CAP256 that targets HIV-1

“…HIV-1 monomeric (gp120 FVC M) or trimeric (gp140 FVC GCN4 or gp140 FVC SOSIP) Env conformations were recombinantly expressed by transient transfection (using PEI) or stably transfected 293F cell lines [74]. All three constructs comprise the inferred Founder virus consensus C sequence (FVC) described previously [75]. The gp120 FVC Monomer and gp140 FVC GCN4 constructs were available in our laboratory and have been described previously [74].…”