51. Boosting of HIV-1 Neutralizing Antibody Responses by a Distally Related Retroviral Envelope Protein
- Author
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Guillaume Stewart-Jones, Emma J. Bowles, Anders Fomsgaard, Marianne Jansson, Hannes Uchtenhagen, Gabriella Scarlatti, David C. Montefiori, Jaap Willem Back, Adnane Achour, Leo Heyndrickx, Anna-Lena Spetz, Steven E. Applequist, Thushan I de Silva, Celia C. LaBranche, and Torben Schiffner
- Subjects
Male ,viruses ,Molecular Sequence Data ,Immunology ,Immunization, Secondary ,Retroviridae Proteins ,Heterologous ,HIV Antibodies ,Biology ,medicine.disease_cause ,Article ,Immune system ,Viral Envelope Proteins ,medicine ,Animals ,Humans ,Immunology and Allergy ,Binding site ,Neutralizing antibody ,B cell ,chemistry.chemical_classification ,Base Sequence ,Simian immunodeficiency virus ,env Gene Products, Human Immunodeficiency Virus ,virus diseases ,Antibodies, Neutralizing ,Virology ,medicine.anatomical_structure ,Epitope mapping ,chemistry ,HIV-1 ,biology.protein ,Female ,Simian Immunodeficiency Virus ,Rabbits ,Glycoprotein - Abstract
Our knowledge of the binding sites for neutralizing Abs (NAb) that recognize a broad range of HIV-1 strains (bNAb) has substantially increased in recent years. However, gaps remain in our understanding of how to focus B cell responses to vulnerable conserved sites within the HIV-1 envelope glycoprotein (Env). In this article, we report an immunization strategy composed of a trivalent HIV-1 (clade B envs) DNA prime, followed by a SIVmac239 gp140 Env protein boost that aimed to focus the immune response to structurally conserved parts of the HIV-1 and simian immunodeficiency virus (SIV) Envs. Heterologous NAb titers, primarily to tier 1 HIV-1 isolates, elicited during the trivalent HIV-1 env prime, were significantly increased by the SIVmac239 gp140 protein boost in rabbits. Epitope mapping of Ab-binding reactivity revealed preferential recognition of the C1, C2, V2, V3, and V5 regions. These results provide a proof of concept that a distally related retroviral SIV Env protein boost can increase pre-existing NAb responses against HIV-1.
- Published
- 2014