title: 2G12-expressing B cell lines may aid in HIV carbohydrate vaccine design strategies.
abstract: The highly conserved cluster of high-mannose glycans on the HIV-1 envelope glycoprotein, gp120, has been highlighted as a target for neutralizing antibodies. 2G12, the first HIV-1 antiglycan neutralizing antibody described, binds with an unusual domain-exchanged structure that creates a high-affinity multivalent binding surface. It is an interesting challenge for rational vaccine design to generate immunogens capable of eliciting domain-exchanged 2G12-like responses. We recently showed that di-mannose recognition by the variable domains of 2G12 is independent of domain exchange but that exchange is critical for virus neutralization. Carbohydrate-based immunogens aimed at inducing 2G12-like antibodies may need to drive both di-mannose recognition and domain exchange through interactions with B cell receptors. Here we assessed the ability of such immunogens to activate mouse B cell lines displaying domain-exchanged wild-type 2G12 (2G12 WT), a non-domain-exchanged Y-shaped variant (2G12 I19R), and germ line 2G12 (2G12 gl). We show that several immunogens, including heat-killed yeast and bacteria, can activate both 2G12 WT and 2G12 I19R B cells. However, only discrete clusters of high-mannose glycans, as on recombinant forms of the HIV-1 envelope trimer and oligodendrons, activate 2G12 WT B cells. Furthermore, no immunogen tested activated 2G12 gl cells. Our results support the hypothesis that in order to drive domain exchange of an antimannose antibody response, a boost with an immunogen displaying discrete clusters of high-mannose glycans not recognized by conventional Y-shaped antibodies will be required. Additionally, a molecule capable of activating 2G12 gl cells might also be required. The results highlight broadly neutralizing antibody-expressing mouse B cells as potentially useful tools for carbohydrate immunogen screening.
authors.affiliation: Department of Immunology and Microbial Science, Scripps Research Institute, La Jolla, California, USA.
authors.forename: Katie J
authors.initials: KJ
authors.lastname: Doores
authors.forename: Michael
authors.initials: M
authors.lastname: Huber
authors.forename: Khoa M
authors.initials: KM
authors.lastname: Le
authors.forename: Sheng-Kai
authors.initials: SK
authors.lastname: Wang
authors.forename: Colleen
authors.initials: C
authors.lastname: Doyle-Cooper
authors.forename: Anthony
authors.initials: A
authors.lastname: Cooper
authors.forename: Ralph
authors.initials: R
authors.lastname: Pantophlet
authors.forename: Chi-Huey
authors.initials: CH
authors.lastname: Wong
authors.forename: David
authors.initials: D
authors.lastname: Nemazee
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Burton
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D000080908:Broadly Neutralizing Antibodies; D002241:Carbohydrates / Q000276:immunology*; D002460:Cell Line; D055808:Drug Discovery / Q000379:methods; D015870:Gene Expression; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice
chemical_list: C529157:2G12 monoclonal antibody; D016915:AIDS Vaccines; D000911:Antibodies, Monoclonal; D000080908:Broadly Neutralizing Antibodies; D002241:Carbohydrates; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; C514793:gp120 protein, Human immunodeficiency virus 1