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CDER Meeting: Surrogate Markers of Immunity

CDER Meeting: Surrogate Markers of Immunity. Presenter: Judith A. Britz, Ph.D. October 16, 2000. HIV Pathogenesis . Cellular Immune Function Tests have Prognostic Value: independent of CD4+ Count Up to 1 year before CD4 Count Decline Progressive Loss of Function as measured by response to:

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CDER Meeting: Surrogate Markers of Immunity

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  1. CDER Meeting: Surrogate Markers of Immunity Presenter: Judith A. Britz, Ph.D. October 16, 2000

  2. HIV Pathogenesis • Cellular Immune Function Tests have Prognostic Value: • independent of CD4+ Count • Up to 1 year before CD4 Count Decline • Progressive Loss of Function as measured by response to: • Mitogens • Alloantigens • Recall Antigens Clerici et al. 1989. J. Clin. Invest. 84: 1892 Dolan et al. 1995. J. Infect. Dis.172:79

  3. Immune Reconstitution • LPA Reactivity to HIV p24 rAg enhanced: • Long Term Non-Progressors • Following early treatment of acute HIV infection • Strengthened by treatment interruption (in some patients) Rosenberg, E.S et al. 1997. Science 278: 1447 Rosenberg, E.S. et al. 2000. Nature 408: 523

  4. Lymphoproliferation (LPA) Traditional method for evaluating cell-mediated immune function: • Time-consuming: 5-7 Days • Radioactive • Labor-intensive • Not widely available • Not standardized • Shipping impact • Not practical for clinical use Betensky et al. 2000. Clin. Diag. Lab. Immunol. 7(5): 759

  5. Objectives • Clinical Correlate of Cell-Mediated Immunity • 24 Hours or less • Non-Radioactive • Whole Blood or PBMCs • Cost Effective • Adaptable to Test with Multiple Antigens • Standardized

  6. Wash Incubate Magnetic separation of CD4 cells. ATP detection reagents ATP Luminometer ATP ATP Cell lysis to release ATP Measure light intensity 4 hours to overnight Lymphocyte Stimulation

  7. Comparison with LPA ATP ng/mL In vitro CMI Overnight DPM x 100 LPA assay 96 HRS

  8. Reference Sottong, P.R., J.A. Rosebrock, J.A. Britz, and T.R. Kramer. 2000. Measurement of T-lymphocyte responses in whole blood cultured using newly synthesized DNA and ATP. Clinical and Diagnostic Laboratory Immunology 7(2): 307-311

  9. PHA Distribution of Normal and HIV+ Patients Normal HIV+ Homi Farzadegan. Johns Hopkins. 2000. IHV Meeting.

  10. Measurement Of Cell Activation By Mitogens And Recall Antigens Therapy Changed B.J. Loechelt, M. Chan Children’s National Medical Center, Washington, D.C; 2000. Manuscript in Preparation.

  11. Measurement Of Cell Activation By Mitogens And Recall Antigens B.J. Loechelt, M. Chan Children’s National Medical Center, Washington, D.C; 2000. Manuscript in preparation

  12. COMPARISON OF RESPONDERS AND NON RESPONDERS TO P24 ANTIGEN IN HIV INFECTION COMPARED TO CONTROLS p<0.01 HIV- Controls HIV+ Non Responders HIV+ Responders ATP Cunningham-Rundles, S. and J. Cervia. Cornell University School of Medicine. 2000. Manuscript in preparation.

  13. Wahren, B. et al. Karolinska Institute. 2000. IHV Meeting

  14. Lymphocyte Response 3 – 7 days Clonal Expansion Proliferation 6 - 24 hours Influx of ions Surface receptor clustering RNA synthesis Cytokine production & release DNA replication Cylex In Vitro CMI Cytokine Assays Lympho-proliferation ATP 1/2 - 6 hours Lymphocyte Stimulation

  15. Analytical Parameters • Accuracy • Precision • Sensitivity • Specificity • Reproducibility • Stability • Standardization

  16. AIDS Patient Management

  17. Acknowledgements • Susanna Cunnigham-Rundles: Cornell • Brett Loechelt: George Washington • Homi Farzadegan: Johns Hopkins • Britta Wahren: Karolinska • Tim Kramer: USDA • Peter Sottong: Cylex • Richard Kowalski: Cylex • Julie Woodcock: Cylex

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