PPHM and Tarvacin discussion

[Preciouslife1]

Principal Investigator: Barton Haynes

Project: Broadly Reactive Neutralizing Antibodies: Novel Strategies for Vaccine Design

Our goal is to acquire proof of concept data that manipulation of the immunoregulatory controls of B cell immune responses to HIV-1 Env, coupled with enhanced immunogen design, can lead to safe induction of broadly reactive neutralizing antibody responses. We are using a two armed approach to the problem of induction of antibodies that broadly neutralize HIV.
The Kelsoe, Haynes and Thorpe laboratories are developing immunogen formulations that trigger B cells normally tolerant to the desired Envelope epitopes and regions. Garnett Kelsoe is determining the origins, development, physiology, and fates of marginal zone, transitional and B1 B cell populations in animal models including mice and non-human primates. Haynes is determining the role of tolerance mechanisms, and TLR signaling on control of broadly reactive B cell activation, and Philip Thorpe is determining the role of lipid binding of anti-HIV antibodies and anti-phosphatidylserine(PS) autoantibodies to protection from HIV infection. With Norm Letvin, a protection trial is being planned to determine if anti-PS antibodies can prevent infection or early viral destruction of the immune system in acute SIV infection.
The Harrison, Alam, Spicer, Shaw, Robinson and Hahn laboratories are developing immunogens that are more “native” and will preferentially induce the desired antibody types. These include HIV Env immunogens with a spectrum of affinities for binding to broadly reactive neutralizing antibodies, and immunogens with low entropic barriers to Mab binding and therefore are thermodynamically stable. Steve Harrison and Bing Chen are expressing and characterizing single-chain Fvs from 4E10, 2F5 and 2G12 Mabs to dissect lipid and protein contributions to binding and Mab neutralization. They will use the Fvs in co-crystallization efforts with trimeric gp120/gp41 constructs. Munir Alam is designing gp41 peptide lipid conjugates using 4E10 and 2F5 epitopes peptides. He is characterizing the binding kinetics, and thermodynamic properties of 4E10 and 2F5 binding to peptide-lipid conjugates. Desaire is characterizing the carbohydrates of HIV-1 Env produced in T cells and macrophages, and Haynes is determining methods for making these “autoantigens” immunogenic. Spicer is studying the lipid-peptide conjugates for their structures by NMR. George Shaw and Beatrice Hahn have constructed HIV-1/HIV-2 chimeras with HIV-2 neutralizing determinants in HIV-1 scaffolds, to study the neutralization of HIV-2.
Interim Report, Submitted on 2/1/08

Our goal is to acquire proof of concept data that manipulation of the immunoregulatory controls of B cell immune responses to HIV-1 Env, coupled with enhanced immunogen design, can lead to safe induction of broadly reactive neutralizing antibody responses. We are using a two armed approach to the problem of induction of antibodies that broadly neutralize HIV.
The Kelsoe, Haynes and Thorpe laboratories are developing immunogen formulations that trigger B cells normally tolerant to the desired Envelope epitopes and regions. Garnett Kelsoe is determining the origins, development, physiology, and fates of marginal zone, transitional and B1 B cell populations in animal models including mice and non-human primates. Haynes is determining the role of tolerance mechanisms, and TLR signaling on control of broadly reactive B cell activation, and Philip Thorpe is determining the role of lipid binding of anti-HIV antibodies and anti-phosphatidylserine (PS) autoantibodies to protection from HIV infection. We have completed the first protection trial to determine if anti-beta-2-glycoprotein-1 antibodies can prevent infection or early viral destruction of the immune system in acute SIV infection.
The Harrison, Alam, Spicer, Shaw, Robinson and Hahn laboratories are developing immunogens that are more native and are being tested for induction of desired antibody types. These include HIV Env immunogens with a spectrum of affinities for binding to broadly reactive neutralizing antibodies, and immunogens with low entropic barriers to Mab binding and therefore are thermodynamically stable. Steve Harrison, Bing Chen and Larry Liao have made single chain Fv 4E10 antibodies and whole IgG1 2F5 Mabs with mutations that selectively eliminate gp41 or lipid reactivity. They have demonstrated that both 2F5 and 4E10 require the capacity to bind to lipids to neutralize HIV-1. They will now use the Fvs and Mabs in co-crystallization efforts with trimeric gp120/gp41 constructs. Munir Alam is designing gp41 peptide lipid conjugates using 4E10 and 2F5 epitopes peptides. He is characterizing the binding kinetics, and thermodynamic properties of 4E10 and 2F5 binding to peptide-lipid conjugates. Heather Desaire is characterizing the carbohydrates of HIV-1 Env produced in T cells and macrophages, and Haynes is determining methods for making these “autoantigens” immunogenic. Spicer is studying the lipid-peptide conjugates for their structures by NMR. George Shaw and Beatrice Hahn have constructed HIV-1/HIV-2 chimeras with HIV-2 neutralizing determinants in HIV-1 scaffolds, to study the neutralization of HIV-2 with James Robinson.