Assessment of Crosslinkers between Peptide Antigen and Carrier Protein for Fusion Peptide-Directed Vaccines against HIV-1
Author:
Ou LiORCID, Gulla Krishana, Biju Andrea, Biner Daniel W., Bylund Tatsiana, Changela Anita, Chen Steven J.ORCID, Zheng Cheng-Yan, Cibelli Nicole, Corrigan Angela R., Duan Hongying, Gonelli Christopher A.ORCID, Kong Wing-Pui, Cheng Cheng, O’Dell Sijy, Sarfo Edward K.ORCID, Shaddeau Andrew, Wang Shuishu, Vinitsky Alison, Yang Yanhong, Zhang Baoshan, Zhang Yaqiu, Koup Richard A., Doria-Rose Nicole A., Gall Jason G., Mascola John R., Kwong Peter D.ORCID
Abstract
Conjugate-vaccine immunogens require three components: a carrier protein, an antigen, and a crosslinker, capable of coupling antigen to carrier protein, while preserving both T-cell responses from carrier protein and B-cell responses from antigen. We previously showed that the N-terminal eight residues of the HIV-1 fusion peptide (FP8) as an antigen could prime for broad cross-clade neutralizing responses, that recombinant heavy chain of tetanus toxin (rTTHC) as a carrier protein provided optimal responses, and that choice of crosslinker could impact both antigenicity and immunogenicity. Here, we delve more deeply into the impact of varying the linker between FP8 and rTTHC. In specific, we assessed the physical properties, the antigenicity, and the immunogenicity of conjugates for crosslinkers ranging in spacer-arm length from 1.5 to 95.2 Å, with varying hydrophobicity and crosslinking-functional groups. Conjugates coupled with different degrees of multimerization and peptide-to-rTTHC stoichiometry, but all were well recognized by HIV-fusion-peptide-directed antibodies VRC34.01, VRC34.05, PGT151, and ACS202 except for the conjugate with the longest linker (24-PEGylated SMCC; SM(PEG)24), which had lower affinity for ACS202, as did the conjugate with the shortest linker (succinimidyl iodoacetate; SIA), which also had the lowest peptide-to-rTTHC stoichiometry. Murine immunizations testing seven FP8-rTTHC conjugates elicited fusion-peptide-directed antibody responses, with SIA- and SM(PEG)24-linked conjugates eliciting lower responses than the other five conjugates. After boosting with prefusion-closed envelope trimers from strains BG505 clade A and consensus clade C, trimer-directed antibody-binding responses were lower for the SIA-linked conjugate; elicited neutralizing responses were similar, however, though statistically lower for the SM(PEG)24-linked conjugate, when tested against a strain especially sensitive to fusion-peptide-directed responses. Overall, correlation analyses revealed the immunogenicity of FP8-rTTHC conjugates to be negatively impacted by hydrophilicity and extremes of length or low peptide-carrier stoichiometry, but robust to other linker parameters, with several commonly used crosslinkers yielding statistically indistinguishable serological results.
Funder
Intramural Research Program of the Vaccine Research Center
Subject
Pharmacology (medical),Infectious Diseases,Drug Discovery,Pharmacology,Immunology
Reference61 articles.
1. Rational Design of Vaccines to Elicit Broadly Neutralizing Antibodies to HIV-1;Kwong;Cold Spring Harb. Perspect Med.,2011 2. HIV-1 Vaccines Based on Antibody Identification, B Cell Ontogeny, and Epitope Structure;Kwong;Immunity,2018 3. Immunogenicity of Stabilized HIV-1 Envelope Trimers with Reduced Exposure of Non-neutralizing Epitopes;de Taeye;Cell,2015 4. Cheng, C., Xu, K., Kong, R., Chuang, G.Y., Corrigan, A.R., Geng, H., Hill, K.R., Jafari, A.J., O’Dell, S., Ou, L., Consistent elicitation of cross-clade HIV-neutralizing responses achieved in guinea pigs after fusion peptide priming by repetitive envelope trimer boosting. PLoS ONE, 2019. 14. 5. Epitope-based vaccine design yields fusion peptide-directed antibodies that neutralize diverse strains of HIV-1;Xu;Nat. Med.,2018
|
|