Broadly neutralizing anfibodies (BNAb) to HIV-1 primarily target the conserved membrane proximal ectodomain region (MPER) of the viral gpl60 envelope protein. We have studied the HxB2 MPER segment in lipid environments by a combinafion of nuclear magnefic resonance (NMR), electron paramagnetic resonance (EPR) and surface plasmon resonance (SPR) methodologies. Structural analyses reveal a tilted N-terminal a-helix (aa 664-672) connected via a short hinge (673-674) to a fiat Cterminal helical segment (675-683), collecfively forming a metastable L-shaped structure immersed in the membrane. The 4E10 BNAb extracts buried W672 and F673 following inifial encounter with the surface embedded MPER while the 2F5 BNAb lifts up residues N-terminal to the hinge region, exposing L669 and W670. BNAb CDRH3 interactions with lipid appear critical for neutralizing activity of both BNAbs. These data have implicafions for vaccine design and suggest how BNAbs can perturb tryptophan residueassociated viral fusion involving the MPER. Here we shall examine how other BNAbs or newly created MPER-binding anfibodies induce conformafional change around W672 and F673 or elsewhere using several disfinct MPER segment sequences. We shall determine whether such structural changes upon anfibody binding are linked to viral neutralization. Moreover, specificity and diversity of antibodies arising during natural HIV-1 infecfion vs. elicited upon vaccinafion will be compared. Sensitive EPR residue depth and inter-residue distance measurements will allow for relatively rapid screening of detectable changes in MPER conformafion. Once identified by EPR, interacfion will be followed by detailed NMR analysis. How lipid constituents of the virosome, including cholesterol, affect the membrane-embedded structure of the MPER, or its ability to undergo conformafional changes upon anfibody binding, will be assessed. In addifion, lipid-enveloped nanoparticles as carriers of natively configured MPER segments, including those with a bioresorbable poly (lactide-co-glycolide)(PLGA) core harboring """"""""universal"""""""" class II MHC binding epitopes for maximal sfimulafion of follicular CD4+ T cell help, will be tested in murine intradermal immunizafion studies aimed at eliciting BNAbs. These nanoparticles, created in Project 2, of differing size and surface characteristics, will be further armed with targeting and immune activating adducts to opfimize the magnitude of the specific immune response using modulators of hypoxia-adenosinergic inhibition defined in Project in Project 4. ELISA, BlAcore and antibody neutralizafion assays will assess the breadth of neutralizing responses.

Public Health Relevance

Given that globally, to date, 65 million human infecfions with HIV-1 have been esfimated, the development of a vaccine elicifing broadly neutralizing antibodies in normal subjects will be an enormous preventive advance in the fight against AIDS.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Program--Cooperative Agreements (U19)
Project #
5U19AI091693-03
Application #
8381801
Study Section
Special Emphasis Panel (ZAI1-PTM-A)
Project Start
Project End
Budget Start
2012-09-01
Budget End
2013-08-31
Support Year
3
Fiscal Year
2012
Total Cost
$1,060,577
Indirect Cost
$362,809
Name
Dana-Farber Cancer Institute
Department
Type
DUNS #
076580745
City
Boston
State
MA
Country
United States
Zip Code
02215
Silva, Murillo; Nguyen, Thao H; Philbrook, Phaethon et al. (2017) Targeted Elimination of Immunodominant B Cells Drives the Germinal Center Reaction toward Subdominant Epitopes. Cell Rep 21:3672-3680
Abbott, Robert K; Silva, Murillo; Labuda, Jasmine et al. (2017) The GS Protein-coupled A2a Adenosine Receptor Controls T Cell Help in the Germinal Center. J Biol Chem 292:1211-1217
Song, Likai; Liu, Zhanglong; Kaur, Pavanjeet et al. (2016) Toward increased concentration sensitivity for continuous wave EPR investigations of spin-labeled biological macromolecules at high fields. J Magn Reson 265:188-96
Shrestha, Ruben; Chen, Xuejie; Ramyar, Kasra X et al. (2016) Identification of Surface-Exposed Protein Radicals and A Substrate Oxidation Site in A-Class Dye-Decolorizing Peroxidase from Thermomonospora curvata. ACS Catal 6:8036-8047
Abbott, Robert K; Thayer, Molly; Labuda, Jasmine et al. (2016) Germinal Center Hypoxia Potentiates Immunoglobulin Class Switch Recombination. J Immunol 197:4014-4020
Donius, Luke R; Cheng, Yuxing; Choi, Jaewon et al. (2016) Generation of Long-Lived Bone Marrow Plasma Cells Secreting Antibodies Specific for the HIV-1 gp41 Membrane-Proximal External Region in the Absence of Polyreactivity. J Virol 90:8875-90
Moyer, Tyson J; Zmolek, Andrew C; Irvine, Darrell J (2016) Beyond antigens and adjuvants: formulating future vaccines. J Clin Invest 126:799-808
Hanson, Melissa C; Crespo, Monica P; Abraham, Wuhbet et al. (2015) Nanoparticulate STING agonists are potent lymph node-targeted vaccine adjuvants. J Clin Invest 125:2532-46
Irvine, Darrell J; Hanson, Melissa C; Rakhra, Kavya et al. (2015) Synthetic Nanoparticles for Vaccines and Immunotherapy. Chem Rev 115:11109-46
Liu, Haipeng; Irvine, Darrell J (2015) Guiding principles in the design of molecular bioconjugates for vaccine applications. Bioconjug Chem 26:791-801

Showing the most recent 10 out of 26 publications