Antibody Light-Chain-Restricted Recognition of the Site of Immune Pressure in the RV144 HIV-1 Vaccine Trial Is Phylogenetically Conserved

Abstract

SUMMARY In HIV-1, the ability to mount antibody responses to conserved, neutralizing epitopes is critical for protection. Here we have studied the light chain usage of human and rhesus macaque antibodies targeted to a dominant region of the HIV-1 envelope second variable (V2) region involving lysine (K)169, the site of immune pressure in the RV144 vaccine efficacy trial. We found that humans and rhesus macaques used orthologous lambda variable gene segments encoding a glutamic acid-aspartic acid (ED) motif for K169 recognition. Structure determination of an unmutated ancestor antibody demonstrated that the V2 binding site was pre-configured for ED motif-mediated recognition prior to maturation. Thus, light chain usage for recognition of the site of immune pressure in the RV144 trial is highly conserved across species. These data indicate the HIV-1 K169-recognizing ED motif has persisted over the diversification between rhesus macaques and humans, suggesting an evolutionary advantage of this antibody recognition mode.

Tissue memory B cell repertoire analysis after ALVAC/AIDSVAX B/E gp120 immunization of rhesus macaques

“…We further analyzed DH614 B cell lineage V2 mAbs on a series of V1V2 peptides that contained amino acid mutations across the 22-amino acid sequence. All mAbs in this lineage were sensitive to mutations at K169 (Figure 9A), consistent with the ED motif described above; these mAbs were sensitive to changes in H173 that was also identified as part of epitope for this class of antibodies (12). CH58 is a human mAb derived from an RV144 trial participant (11) that was sensitive to changes at both K169 and H173, and also to changes at K168, K171, F176, Y177, K178, D180, and P183; the mAbs of the DH614 lineage showed sensitivity to all of these changes except P183, but the degree of sensitivity varied between members of this lineage ( Figure 9A), demonstrating ongoing affinity changes.…”

“…This lineage potently neutralized AE.92TH023.6 while still neutralizing B.MN.3, and may be reflective of tier 1 neutralizing antibodies that correlated with decreased infection risk in RV144 (5). The DH612 and DH163 lineages were not directed against the V1V2 loop, and these data combined with the previously reported V1V2-directed mAbs (12) demonstrate that RMs are capable of mounting a multiple-epitope, cross-clade response to the ALVAC/AIDSVAX B/E regimen.…”

“…Of the clonal lineages described above, we selected 4 lineages distributed across multiple tissues that either neutralized HIV-1 or that bound to the surface of HIV-1-infected CD4 + T cells as required for ADCC, in order to compare these lineages to mAbs isolated from RV144 participants (11,17,19) and to determine their detailed binding and/or functional activities. The 8-member DH614 lineage was found in 5 different anatomic sites, and this lineage used the same lambda chain gene associated with recognition of K169 (12). The unmutated common ancestor (UCA) of this lineage weakly bound the V1V2 tag AE.A244 protein at high antibody concentrations (data not shown) but did not neutralize ( Figure 8A).…”

“…The mature antibodies of this lineage very potently bound Env proteins and V1V2 tags, but these antibodies did not bind gp120 AE.703357 , an Env protein derived from one of the placebo group infections in the RV144 trial that has a glutamine at position 169 (Q169) (11). All members of this lineage have the glutamic acid/aspartic acid (ED) motif described for other antibodies of this class (12). All mature lineage members potently bound Env proteins and AE.CM235-infected cells; however, neutralization potency varied among the members ( Figure 8A).…”

“…Sequencing of the transmitted/founder viruses isolated from RV144 vaccinees that did become infected demonstrated the lysine at position 169 (K169) in the V2 region as a site of selection pressure (10). Analyses of mAbs representative of the putative protective antibodies from RV144 subjects showed that the V2 K169-centered epitope is recognized by antibodies with restricted variable heavy (V H ) and variable light (V L ) chain gene usage (11) and that V L restriction for recognition of the V2 epitope around K169 is conserved throughout primate phylogeny (12). Thus, the current hypothesis is that ADCC or other Fc receptor-mediated (FcR-mediated) anti-HIV-1 functions of V2 and other Env antibodies were the likely correlates of protection (7,(13)(14)(15)(16).…”