Evaluating Viral Antigens and Antibody Neutralization for HIV/AIDS, Smallpox, and Influenza

Principal Investigator: Carol D. Weiss, MD
Office / Division / Lab: OVRR / DVP / LI

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Overview

Public Health Issue: Neutralizing antibodies can protect against HIV, smallpox, and influenza viruses. Development of safe and effective vaccines that can generate broadly neutralizing antibodies to HIV, smallpox, and influenza viruses would have a major impact on global health.

Regulatory Contribution: Proteins on the envelope (Env) of HIV, influenza, and poxviruses can induce neutralizing antibodies that protect against infection. HIV Env does not efficiently induce broadly neutralizing antibodies that will protect against many HIV strains, so studies of the immunogenicity and antigenicity of conserved Env structures are needed to develop potent and broadly-active HIV vaccines. For smallpox, several vaccinia Env proteins appear to induce protective antibodies, but it remains unclear which responses are necessary or sufficient for complete protection. Studies on antibody specificities that are important for protection should provide valuable information for evaluating new smallpox vaccines. For influenza, antibodies that have neutralizing and hemagglutinin inhibition activity are important correlates of protection that are used to evaluate new vaccines. New information on the performance of antisera to various subtypes of influenza in different neutralization and hemagglutinin inhibition assays should aid evaluations of new influenza vaccines. We are especially interested in developing and validating a neutralization assay using non-replicating viral pseudotypes. The availability of this assay will allow for evaluation of antibody neutralization of pandemic influenza strains that can be performed widely without the need for high-level biocontainment facilities.

Research Approach: This research program uses biochemical, immunological, and genetic approaches to investigate neutralizing determinants in Env proteins of HIV, vaccinia, and influenza viruses. For HIV studies, the research focuses on elucidating the Env conformation and structural determinants that allow broadly neutralizing antibodies and inhibitors to bind Env and how antibodies to these conserved regions can be elicited by rationally designed vaccines that are based on structure-function data of Env. For vaccinia studies, research focuses on dissecting neutralizing and protective antibody responses elicited by Dryvax and comparing those responses with those induced by new non-replicating vaccines. The immunogenicity of new vaccines needs to be compared to Dryvax, because there can be no true efficacy trial in the absence of circulating smallpox. Influenza studies focus on comparative evaluations of HA antisera in a variety of functional assays, especially focusing on non-replicating, high-throughput reporter assays to assess virus neutralizing activity. This work will involve further optimization of our current HA pseudotype neutralization assays using various H5 strains and further quantification of the specificity, sensitivity, and robustness, compared to other assays.

Mission Relevance & Outcomes: Information gained from our research will facilitate the development and evaluation of new vaccines for HIV/AIDS, smallpox, and influenza. The HIV program has already influenced the field in pursuing new approaches for designing HIV vaccines that target conserved functional domains in the transmembrane protein and current work should provide more insights in to rational vaccine design. The smallpox program has dissected contributions of one key protein to protective immune responses induced by Dryvax. The influenza program has developed safe, robust, and sensitive assays for evaluating neutralizing activity in sera against H5, H1 and H3 subtypes influenza. This assay does not require replicating influenza virus and has been shown to correlate well with classical assays that use replicating virus. Additional data about how this assay performs against existing assays should aid the field in determining the usefulness of adopting this safe assay that reduces the need to work with replicating virus.

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Publications

J Virol Methods 2008 Nov;153(2):111-9
Establishment of retroviral pseudotypes with influenza hemagglutinins from H1, H3, and H5 subtypes for sensitive and specific detection of neutralizing antibodies.
Wang W, Butler EN, Veguilla V, Vassell R, Thomas JT, Moos M, Ye Z, Hancock K, Weiss CD

J Infect Dis 2007 Oct 1;196(7):1026-32
Antibodies to the A27 Protein of Vaccinia Virus Neutralize and Protect against Infection but Represent a Minor Component of Dryvax Vaccine-Induced Immunity.
He Y, Manischewitz J, Meseda CA, Merchlinsky M, Vassell RA, Sirota L, Berkower I, Golding H, Weiss CD

Virology 2005 Dec 5;343(1):128-40
Identification and preliminary characterization of vaccinia virus (Dryvax) antigens recognized by vaccinia immune globulin.
Jones-Trower A, Garcia A, Meseda CA, He Y, Weiss C, Kumar A, Weir JP, Merchlinsky M

J Virol 2005 Apr;79(8):4774-81
Human Immunodeficiency Virus (HIV) gp41 Escape Mutants: Cross-Resistance to Peptide Inhibitors of HIV Fusion and Altered Receptor Activation of gp120.
Desmezieres E, Gupta N, Vassell R, He Y, Peden K, Sirota L, Yang Z, Wingfield P, Weiss CD

J Virol 2004 Mar 1;78(5):2627-2631
Binding of the 2F5 Monoclonal Antibody to Native and Fusion-Intermediate Forms of Human Immunodeficiency Virus Type 1 gp41: Implications for Fusion-Inducing Conformational Changes.
De Rosny E, Vassell R, Jiang S, Kunert R, Weiss CD

Blood 2004 Mar 1;103(5):1586-94
Thiol/disulfide exchange is a prerequisite for CXCR4-tropic HIV-1 envelope-mediated T-cell fusion during viral entry.
Markovic I, Stantchev TS, Fields KH, Tiffany LJ, Tomic M, Weiss CD, Broder CC, Strebel K, Clouse KA