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Reinherz Progress Report Abstracts continued

 
Submitted July 1, 2011

The overarching goal of this project is to elicit broadly neutralizing anti-HIV-1 antibodies to the distal membrane proximal ectodomain region (MPER) of gp41 predicated on i) structure-based immunogen design and ii) nanoparticle delivery through targeted uptake. NMR and EPR-based structural analysis demonstrates the presence of a hinge between the N and C helical segments of the MPER of additional clade C HIV-1 sequences studied in the context of the lipid membrane. Immunogenicity studies are underway but already demonstrate that presentation of the MPER embedded on lipid-based particles/liposomes stimulates B cell responses capable of recognizing this segment.

 
Submitted July 1, 2011

The overarching goal is to elicit broadly neutralizing anti-HIV-1 antibodies to the distal
membrane proximal ectodomain region (MPER) of gp41 predicated on i) structure-based
immunogen design and ii) nanoparticle delivery through targeted uptake. Our main focus on
structural analysis of clade C is: 1) how sequence changes in the MPER affect its overall
conformation and interaction with the membrane, 2) how MPER/membrane interaction and/or
subtle changes in membrane depth influenced by sequence variation including hinge area may
affect antigenicity and antibody neutralization potency and 3) how the TM segment affects
conformation of the MPER with and without 4E10 binding, particularly the C helical segment
distal to the structural hinge. Those structural data combined with systematic analysis of
antigen/nanoparticle integrity during delivery to regional lymph node will be incorporated to
immunogen design and nanoparticle vaccine formulation to best deliver the MPER in the native
configuration. The Irvine group is focusing on creation of multi-functional stealth liposomes,
interbilayer crosslinked multilamellar vesicles or nanoparticles consisting of a PLGA core
particle and encapsulated by an outer lipid vesicle or "skin" for MPER presentation to the
immune system. The Irvine group has carried out studies optimizing syntheses of lipid-coated
poly(lactide-co-glycolide) and liposomal nanoparticles that co-display Toll-like receptor (TLR)
ligands and HIV MPER peptides in their lipid surfaces for testing as MPER immunogen delivery
agents. It was found that size of particles is critical to lymph node trafficking and subsequent
immunogenicity.We have also begun to carry out systematic immunogenicity studies of the
MPER induced by vaccination. This involves studies on adjuvants effect, immunization route,
precise correlation between neutralization and conformational changes of the MPER induced by
antibody and the neutralization potency specifically elicited against the MPER (involvement of
lipid binding, specific locale of epitope in the MPER or antibody affinity, etc.). Antigen integrity
during delivery to B cells as well as antigen compartmentalization in LN by different routes has
been studied through systematic analysis of antigen/nanoparticle integrity during delivery to the
regional lymph node. Conformational differences in MPER segments result from parahinge
residue alterations and impact immunogenicity. Optimization of T cell help and TLRs is underway.

 
Submitted July 9, 2010

The overarching goal of this project is to elicit broadly neutralizing anti-HIV-1 antibodies to the distal
membrane proximal ectodomain region (MPER) of gp41 predicated on i) structure-based immunogen
design and ii) nanoparticle delivery through targeted uptake. NMR and EPR-based structural analysis
demonstrates the presence of a hinge between the N and C helical segments of the MPER of additional
clade C HIV-1 sequences studied in the context of the lipid membrane. Immunogenicity studies are
underway but already demonstrate that presentation of the MPER embedded on lipid-based
particles/liposomes stimulates B cell responses capable of recognizing this segment.

 
Submitted December 30, 2009 (Interim Report)

The overarching goal is to elicit broadly neutralizing anti-HIV-1 antibodies to the distal membrane proximal ectodomain region (MPER) of gp41 predicated on i) structure-based immunogen design and ii) nanoparticle delivery through targeted uptake. Our main focus on structural analysis of clade C is: 1) how sequence changes in the MPER affect its overall conformation and interaction with the membrane, 2) how MPER/membrane interaction and/or subtle changes in membrane depth influenced by sequence variation including hinge area may affect antigenicity and antibody neutralization potency and 3) how the TM segment affects conformation of the MPER with and without 4E10 binding, particularly the C helical segment distal to the structural hinge. Those structural data combined with systematic analysis of antigen/nanoparticle integrity during delivery to regional lymph node will be incorporated to immunogen design and nanoparticle vaccine formulation to best deliver the MPER in the native configuration. The Irvine group is focusing on creation of multi-functional liposomes or nanoparticles consisting of a PLGA core particle and encapsulated by an outer lipid vesicle or "skin" for MPER presentation to the immune system. The Irvine group carries out studies optimizing syntheses of lipid-coated poly(lactide-co-glycolide) and liposomal nanoparticles that co-display Toll-like receptor (TLR) ligands and HIV MPER peptides in their lipid surfaces for testing as MPER immunogen delivery agents. In addition, studies will focus on the enhanced shelf-life of nanoparticles and control over kinetics of encapsulated antigen/adjuvant release compared to liposomal delivery. They will address the well-known issues of stability and ‘leakiness’ of liposomes. We will also carry out systematic immunogenicity studies of the MPER induced by vaccination. This involves studies on adjuvants effect, immunization route, precise correlation between neutralization and conformational changes of the MPER induced by antibody and the neutralization potency specifically elicited against the MPER (involvement of lipid binding, specific locale of epitope in the MPER or antibody affinity, etc.). Antigen integrity during delivery to B cells as well as antigen compartmentalization in LN by different routes is also being studied through systematic analysis of antigen/nanoparticle integrity during delivery to the regional lymph node.

 
Submitted July 1, 2009

The overarching goal is to elicit broadly neutralizing anti-HIV-1 antibodies to the distal membrane proximal ectodomain region (MPER) of gp41 predicated on i) structure-based immunogen design and ii) nanoparticle delivery through targeted uptake.

Reinherz, Wagner, Kim, Song and Sun focus on the structural analysis of HIV-1 MPER from clade C viruses and related immunogens in lipid environments using NMR, EPR and SPR technologies. The study is to understand 1) how sequence changes in the MPER affect its overall conformation and interaction with the membrane, 2) how MPER/membrane interaction and/or subtle changes in membrane depth influenced by sequence variation including hinge area may affect antigenicity and antibody neutralization potency and 3) how the TM segment affects conformation of the MPER with and without 4E10 binding, particularly the C helical segment distal to the structural hinge.

The Irvine group is focusing on creation of multi-functional liposomes or MPER nanocells consisting of a PLGA core particle and encapsulated by an outer lipid vesicle or "skin" for MPER presentation to the immune system. In addition, studies will focus on the enhanced shelf-life of nanoparticles and control over kinetics of encapsulated antigen release compared to liposomal delivery. They will address the well-known issues of stability and ‘leakiness’ of liposomes. The Irvine group carries out studies optimizing syntheses of lipid-coated poly(lactide-co-glycolide) and liposomal nanoparticles that co-display Toll-like receptor (TLR) ligands and HIV MPER peptides in their lipid surfaces.

Reinherz and Kim are carrying out systematic immunogenicity studies of the MPER induced by vaccination. This involves studies on adjuvants effect, immunization route, precise correlation between neutralization and conformational changes of the MPER induced by antibody and the neutralization potency specifically elicited against the MPER (involvement of lipid binding, specific locale of epitope in the MPER or antibody affinity, etc.). Antigen integrity during delivery to B cells as well as antigen compartmentalization in LN by different routes is also being studied and are under investigation through careful multi-color immunohistochemistry work.

 
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