Induction of HIV-1 broad neutralizing antibodies in 2F5 knock-in mice: selection against membrane proximal external region-associated autoreactivity limits T-dependent responses.

TitleInduction of HIV-1 broad neutralizing antibodies in 2F5 knock-in mice: selection against membrane proximal external region-associated autoreactivity limits T-dependent responses.
Publication TypeJournal Article
Year of Publication2013
AuthorsVerkoczy L, Chen Y, Zhang J, Bouton-Verville H, Newman A, Lockwood B, Scearce RM, Montefiori DC, Dennison MS, Xia S-M, Hwang K-K, Liao H-X, Alam MS, Haynes BF
JournalJournal of immunology (Baltimore, Md. : 1950)
Volume191
Issue5
Pagination2538-50
Date Published2013 Sep 1
Abstract

A goal of HIV-1 vaccine development is to elicit broadly neutralizing Abs (BnAbs). Using a knock-in (KI) model of 2F5, a human HIV-1 gp41 membrane proximal external region (MPER)-specific BnAb, we previously demonstrated that a key obstacle to BnAb induction is clonal deletion of BnAb-expressing B cells. In this study of this model, we provide a proof-of-principle that robust serum neutralizing IgG responses can be induced from pre-existing, residual, self-reactive BnAb-expressing B cells in vivo using a structurally compatible gp41 MPER immunogen. Furthermore, in CD40L-deficient 2F5 KI mice, we demonstrate that these BnAb responses are elicited via a type II T-independent pathway, coinciding with expansion and activation of transitional splenic B cells specific for 2F5's nominal gp41 MPER-binding epitope (containing the 2F5 neutralization domain ELDKWA). In contrast, constitutive production of nonneutralizing serum IgGs in 2F5 KI mice is T dependent and originates from a subset of splenic mature B2 cells that have lost their ability to bind 2F5's gp41 MPER epitope. These results suggest that residual, mature B cells expressing autoreactive BnAbs, like 2F5 as BCR, may be limited in their ability to participate in T-dependent responses by purifying selection that selectively eliminates reactivity for neutralization epitope-containing/mimicked host Ags.

DOI10.1371/journal.pone.0072920
Alternate JournalJ. Immunol.