RESUMO
UNLABELLED: Eliciting broadly reactive functional antibodies remains a challenge in human immunodeficiency virus type 1 (HIV-1) vaccine development that is complicated by variations in envelope (Env) subtype and structure. The majority of new global HIV-1 infections are subtype C, and novel antigenic properties have been described for subtype C Env proteins. Thus, an HIV-1 subtype C Env protein (CO6980v0c22) from an infected person in the acute phase (Fiebig stage I/II) was developed as a research reagent and candidate immunogen. The gp145 envelope is a novel immunogen with a fully intact membrane-proximal external region (MPER), extended by a polylysine tail. Soluble gp145 was enriched for trimers that yielded the expected "fan blade" motifs when visualized by cryoelectron microscopy. CO6980v0c22 gp145 reacts with the 4E10, PG9, PG16, and VRC01 HIV-1 neutralizing monoclonal antibodies (MAbs), as well as the V1/V2-specific PGT121, 697, 2158, and 2297 MAbs. Different gp145 oligomers were tested for immunogenicity in rabbits, and purified dimers, trimers, and larger multimers elicited similar levels of cross-subtype binding and neutralizing antibodies to tier 1 and some tier 2 viruses. Immunized rabbit sera did not neutralize the highly resistant CO6980v0c22 pseudovirus but did inhibit the homologous infectious molecular clone in a peripheral blood mononuclear cell (PBMC) assay. This Env is currently in good manufacturing practice (GMP) production to be made available for use as a clinical research tool and further evaluation as a candidate vaccine. IMPORTANCE: At present, the product pipeline for HIV vaccines is insufficient and is limited by inadequate capacity to produce large quantities of vaccine to standards required for human clinical trials. Such products are required to evaluate critical questions of vaccine formulation, route, dosing, and schedule, as well as to establish vaccine efficacy. The gp145 Env protein presented in this study forms physical trimers, binds to many of the well-characterized broad neutralizing MAbs that target conserved Env epitopes, and induce cross-subtype neutralizing antibodies as measured in both cell line and primary cell assays. This subtype C Env gp145 protein is currently undergoing good manufacturing practice production for use as a reagent for preclinical studies and for human clinical research. This product will serve as a reagent for comparative studies and may represent a next-generation candidate HIV immunogen.
Assuntos
Vacinas contra a AIDS/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/genética , Animais , Avaliação Pré-Clínica de Medicamentos , Anticorpos Anti-HIV/imunologia , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , HIV-1/genética , Humanos , Leucócitos Mononucleares/imunologia , Dados de Sequência Molecular , Testes de Neutralização , Coelhos , Vacinação , Produtos do Gene env do Vírus da Imunodeficiência Humana/administração & dosagem , Produtos do Gene env do Vírus da Imunodeficiência Humana/genéticaRESUMO
OBJECTIVES: There is a need to develop HIV-1 vaccine formulations that incorporate inexpensive antigens and clinically acceptable potent adjuvants for inducing neutralizing antibodies. The purpose of this initial vaccine study was to produce peptide- and lipid-induced murine mAbs that replicate the characteristics of the 2F5 and/or 4E10 human antibodies in binding both to the membrane proximal external region (MPER) of glycoprotein 41 and the adjacent lipid bilayer for neutralizing HIV-1 infection of CD4 lymphocytes. RESEARCH DESIGNS AND METHODS: Liposomes containing a synthetic MPER peptide as a peptide antigen, phosphatidylinositol-4-phosphate (PIP) as a lipid antigen, and monophosphoryl lipid A as a potent adjuvant were used as a formulation to immunize mice. mAbs were then produced and tested for binding to MPER, glycoprotein 41, and PIP and for the ability to neutralize HIV-1 infection of CD4 cells in a human peripheral blood mononuclear cell assay. RESULTS: Polyclonal antisera contained antibodies that bound both to MPER and PIP. Immunoglobulin M mAbs were produced that bound both to the core MPER site of 2F5, or that overlapped with the 4E10 site, and that simultaneously bound PIP. High concentrations of these mAbs neutralized infection of peripheral blood lymphocytes by a primary infectious molecular clone of HIV-1. CONCLUSION: Liposomes containing MPER peptide as an antigen, PIP as a lipid antigen, and lipid A as an adjuvant induce anti-MPER-specific multispecific antibodies that simultaneously bind glycoprotein 41 MPER and adjacent lipid and neutralize HIV-1 infection in a human peripheral blood mononuclear cell assay.