Future Directions in HIV Basic Science Research: The Hunt for a Cure

1. Future directions in HIV basic science research The hunt for a cure

2. Future Directions • A new vaccine approach. • Targeting and purging the latent reservoirs. • Targeting and removing integrated virus. • Stem cell based therapies. • Targeting and controlling immune activation.

3. A “new” vaccine approach- Use another virus to “trick” the immune response to SIV • Rhesus Cytomegalovirus is a monkey herpesvirus. • They replaced genes in Rhesus Cytomegalovirus with those of SIV.

4. Annual Reviews

5. Less restricted. Rhesus Cytomegalovirus that expresses SIV genes (strain 68-1 RhCMV) expands the CD8+ T cell response to SIV. N Goonetilleke, and A J McMichael Science 2013;340:937-938 Published by AAAS

6. A new vaccine approach • They found that vaccination with Rhesus Cytomegalovirus containing SIV allowed protection from SIV challenge in monkeys (Rhesus Macaques) • The immune responses in these animals were not the same as the responses in animals exposed to SIV without the vaccine = better protection

7. Targeting and purging the latent reservoirs • HIV latency and persistence is the biggest hurdle in a cure. • Targeting and removing the latent reservoir from the body remains an important therapeutic target.

8. HIV persistence during therapy Short-lived infected cell Long-lived infected cell (latently infected)

9. HIV persistence during therapy Antiretroviral therapy Short-lived infected cell Long-lived infected cell (latently infected)

10. HIV persistence during therapy Short-lived infected cell Long-lived infected cell (latently infected)

11. HIV persistence during therapy Antiretroviral therapy • Latently infected CD4+ T lymphocytes are rare in vivo: • Approximately 1 per 106 total resting CD4+ T cells • Probably constitute around 105-106 cells per patient

12. Formation of HIV latency

13. Infected Cell gp120 Pseudomonas Exotoxin Anti-HIV Immunotoxin Anti-gp120 3B3:N31H/Q100eY(dsFv)-PE McHugh et al.; 2002

14. Prostratin or Bryostatin or ?

16. Activation/elimination strategy for clearing latently-infected cells: Marsden and Zack (2010) Future Virol. 5(1): 97–109.

17. Targeting Integrated Virus

19. HIV Lifecycle

20. Structures of cleavage enzymes. Schiffer J T et al. J. Virol. 2012;86:8920-8936

21. Targeted gene knockout by DNA-editing enzymes. Schiffer J T et al. J. Virol. 2012;86:8920-8936

22. Integrated Virus Targeting • Highly specific, efficient way of getting integrated virus out of cell. • Problems with delivery to the cell. • Highly promising

23. Stem Cell Based Therapies • Most include gene therapy to modify the hosts genetic makeup to: • Make cells that are resistant to HIV infection And/or • Make cells that can target and kill HIV infected cells.

24. http://www.nytimes.com/2011/11/29/health/new-hope-of-a-cure-for-hiv.html?pagewanted=allhttp://www.nytimes.com/2011/11/29/health/new-hope-of-a-cure-for-hiv.html?pagewanted=all

25. Stem cell based Anti-HIV Gene Therapy Containing at least 1 anti-HIV gene Kitchen SG et al. Stem cell-based anti-HIV gene therapy. Virology. 2011

26. Multiple anti-HIV gene therapy approach • Selected anti-HIV genes • Potent HIV inhibitors at early stage of viral life cycle • Distinct anti-HIV mechanisms • Goals • Inhibit multiple HIVs • CCR5 tropic HIVs • CXCR4 tropic HIVs • Multi-drug resistant HIVs • Prevent emergence of resistant HIV mutants CCR5-siRNA Hu-TRIMcyp C46 entry inhibitor HIV TCR

27. “Engineered Immunity” • Stem cell based approaches • Would allow direct genetic modification of progenitor (“baby”) cells in the body • Would allow prolonged self-renewal of modified cells that would have long life in the body • Cells would undergo normal development and be recognized as part of the body

28. Engineering Antiviral Immunity Goal: We are interested in using molecularly cloned, HIV- specific T cell receptors (TCRs) from HIV-specific CD8+ T cells and other HIV-targeting molecules to modify human blood forming stem cells to target and kill HIV in infected individuals

29. “Genetic Vaccination” to HIV Stem cell Viral Vectors Containing Cloned TCRs T cell T cell T cell T cell T cell TCR  TCR  TCR  TCR  TCR  TCR  TCR  TCR  Virus Infected cells

30. Humanized Mouse Model of HIV Infection: The NSG-CTL Model CD34+ CD34+ CD34+ CD34+ CD34+ CD34+ CD34+ CD34+ HLA-A*0201+ Tissue 4. Thaw and Transduce with Anti-HIV TCR Or Control TCR Fetal Liver 1. Sort CD34+ Infect with HIV-1NL4-3HSA-HA 2a. Viably freeze fraction Irradiate 6. Analyze TCR Expression/Function 6-12 weeks 2. Transduce with Anti-HIV TCR or Control TCR 3 weeks 5. Tail Vein Inject NSG NSG • Combine with fetal thymus tissue and liver stroma, implant under kidney capsule

31. HIV-Specific TCR suppresses of HIV in humanized mice Kitchen et al., PLoS Pathogens 2012

32. GMP Level Closed System Gene Transduction and Cell Processing Apheresis Final Infusion Product Cytomate Gene Transfer Product Isolex Culture Isolex

33. Targeting Immune Activation and HIV • HIV activates the immune response during infection • HIV replicates in an active immune response • We can target the virus (ARV), we need to also target the immune response to make it better able to clear HIV • One way is to target specific molecules to lower levels of immune activation to decrease HIV levels.

34. HIV infection in the gut (Intestines, Colon) causes problems with the immune response

35. Immune activation and inflammation in HIV‐1 infection: causes and consequences There is a lot going on in HIV infection. Like antiretroviral therapy and the HIV lifecycle, if we can target multiple events we may be able to allow the immune response to clear HIV. The Journal of PathologyVolume 214, Issue 2, pages 231-241, 27 DEC 2007 DOI: 10.1002/path.2276http://onlinelibrary.wiley.com/doi/10.1002/path.2276/full#fig1