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Viral and Host Factors in the Pathogenesis of HIV-1 Infection: An Overview. Laboratory of Molecular Virology . Subhash Dhawan, Ph.D. Senior Investigator and Chief, Immunopathogenesis Section Laboratory of Molecular Virology Division of Emerging and Transfusion Transmitted Diseases
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Viral and Host Factors in the Pathogenesis of HIV-1 Infection: An Overview Laboratory of Molecular Virology Subhash Dhawan, Ph.D. Senior Investigator and Chief, Immunopathogenesis Section Laboratory of Molecular Virology Division of Emerging and Transfusion Transmitted Diseases Center for Biologics Evaluation and Research United States Food and Drug Administration
Research and Regulatory Responsibilities • Review of Product Applications • Inspection of manufacturing facilities Specific aims (Research): (i) Examine a role of HIV-Tat protein in viral pathogenesis (ii) Understand the involvement of host factors in HIV pathogenesis (iii) Develop strategies to enhance sensitivity of diagnostic assays
HIV-Tat Protein • HIV-Tat is a 9.6 kD protein, believed to be involved in the progression of HIV infection, development of Kaposi’s sarcoma, immunoprogression, apopotosis of normal cells and various neurological disorders • High levels of anti-Tat antibodies relate to low viral load in seropositive non-progressors • A strategy to target functional epitopes may provide a therapeutic approach to reduce disease progression in HIV infection
Tat-induced Cytopathic Effects[The Journal of Immunology 163:15-20 (1999)]
Summary of Results • Cys-rich and Arg-rich Tat sequences represent key pathogenic domains in the HIV-Tat protein • The synthetic HIV-Tat-MPC construct was highly immunogenic and antibodies against it inhibited Tat-induced cytopathic effects • Selective side-chain modification of Cys and Arg residues completely blocked functional activity of these peptides to promote cytopathic effects in HIV-infected monocytes • Selective modification of functional HIV-Tat domains retained immunological characteristics, but completely blocked their pathogenic effects
II. Signal Amplification Conjugates[Peptides 23: 2091-2098, 2002]
Detection of HIV-1 Protein Bands by Western Blot Analysis Using Poly-HRP-Antibody Conjugates[Peptides 23: 2091-2098, 2002]
Summary of Results and Future Plans • Signal amplification conjugates substantially increased the sensitivity of immunoassays • This system will be utilized for amplifying detection signal in nucleic acid assays • Future Plans: • 1. Immunize rhesus with HIV-1 Tat MPC, challenge them with SHIV 89.6 viral strain, and study the progression of disease by measuring viral load and examining tissues by histopathology. • 2. Test commercially available panels of normal serum, serum specimens with low titer of HIV-1 antibodies, and seroconversion panels using signal amplification conjugates and develop highly sensitive assays for the detection of HIV-1 and other infections.