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Search for a cure of HIV/AIDS Dr. Yuntao Wu Depatment of Molecular and Microbiology George Mason University, Manassas, VA.

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Presentation on theme: "Search for a cure of HIV/AIDS Dr. Yuntao Wu Depatment of Molecular and Microbiology George Mason University, Manassas, VA."— Presentation transcript:

1 Search for a cure of HIV/AIDS Dr. Yuntao Wu Depatment of Molecular and Microbiology George Mason University, Manassas, VA

2 Early History of AIDS In March 1981, at least 8 cases of Kaposi’s Sarcoma (KS) have occurred amongst young gay man in New York. By April, CDC noticed an increase in PCP (pneumocystis carinii pneumonia). In June, CDC published a report about PCP in 5 men in Los Angeles. Then, CDC formed a Task Force on KS and Opportunistic Infections. In July, CDC reported KS in 26 gay men in New York City.

3 Between June 1st - May 28, CDC received 355 KS/PCP reports, 79% were homosexual The disease were initially called GRID: Gay-Related Immune Deficiency - In July 1982, first non-homosexual case reports appeared that the disease was occurring in Haitians and Haemophiliacs. - In the same month, AIDS was suggested in a meeting in Washington DC.

4 From The purplish lesions of Kaposi's sarcoma, a cancer not usually seen in young men, were common among the patients with the new immune deficiency disease.

5 Thrush: Oral Candidiasis

6 The Discovery of the AIDS Virus - HIV in 1983 Luc Montagnier HIV-1LAV (HIV-1Lai/LAV) Robert Gallo HTLV-IIIB (HIV-1Lai/IIIB) Jay A Levy UCSF

7 Isolation of a T-Lymphotropic Retrovirus from a Patient at Risk for Acquired Immune Deficiency Syndrome (AIDS) F. Barre-Sinoussi; J. C. Chermann; F. Rey; M. T. Nugeyre; S. Chamaret; J. Gruest; C. Dauguet;C. Axler-Blin; F. Vezinet-Brun; C. Rouzioux; W. Rozenbaum; L. Montagnier Science, New Series, Vol. 220, No. 4599. (May 20, 1983), pp. 868-871.

8 HIV-1 gp120 gp41 p17 p24 RT IN RNA PR Nef

9 What is AIDS ? (Acquired Immunodeficiency Syndrome) 1993 CDC revised definition: HIV-1 infected persons who have less than 200 CD4 T cells per ul or a CD4 percentage of total lymphocytes of less than 14%. 26 clinical conditions

10 Candidiasis of bronchi, trachea, or lungs Candidiasis, esophageal Cervical cancer, invasive * Coccidioidomycosis, disseminated or extrapulmonary Cryptococcosis, extrapulmonary Cryptosporidiosis, chronic intestinal (greater than 1 month's duration) Cytomegalovirus disease (other than liver, spleen, or nodes) Cytomegalovirus retinitis (with loss of vision) Encephalopathy, HIV-related Herpes simplex: chronic ulcer(s) (greater than 1 month's duration); or bronchitis, pneumonitis, or esophagitis Histoplasmosis, disseminated or extrapulmonary Isosporiasis, chronic intestinal (greater than 1 month's duration) Kaposi's sarcoma Lymphoma, Burkitt's (or equivalent term) Lymphoma, immunoblastic (or equivalent term) Lymphoma, primary, of brain Mycobacterium avium complex or M. kansasii, disseminated or extrapulmonary Mycobacterium tuberculosis, any site (pulmonary * or extrapulmonary) Mycobacterium, other species or unidentified species, disseminated or extrapulmonary Pneumocystis carinii pneumonia Pneumonia, recurrent * Progressive multifocal leukoencephalopathy Salmonella septicemia, recurrent Toxoplasmosis of brain Wasting syndrome due to HIV

11 The Possible Origins of HIV-1 - likely transmitted to man from chimpanzees infected with SIVcpz in West Africa. However, Chimpanzees may not be the original reservoir Pan troglodytes

12 The Possible Origin of HIV-2 - likely transmitted to man from SIVsmm- infected sooty mangabeys in west Africa

13 Adults and children estimated to be living with HIV Total: 37.8 (34.6 – 42.3) million Western Europe 580 000 [460 000 – 730 000] North Africa & Middle East 480 000 [200 000 – 1.4 million] Sub-Saharan Africa 25.0 million [23.1 – 27.9 million] Eastern Europe & Central Asia 1.3 million [860 000 – 1.9 million] South & South-East Asia 6.5 million [4.1 – 9.6 million] Oceania 32 000 [21 000 – 46 000] North America 1.0 million [520 000 – 1.6 million] Caribbean 430 000 [270 000 – 760 000] Latin America 1.6 million [1.2 – 2.1 million] East Asia 900 000 [450 000 – 1.5 million]

14 Clinic Course of HIV Infection G. Pantaleo, C. Graziosi, and A.S. Fauci 1993a.. N. Engl. J. Med. 328: 327-335.

15 HIV Replication Cycle RNA DNA RT tat,rev,nef Env,vif,vpr,vpu gag,pol Transcription Integration rev tat nef CD4 CXCR4 or CCR5

16 Reverse Transcriptase Inhibitor by Dan Stowell ©2002-2005). Zidovudine (AZT), Tenofovin, ddI, ddC, d4T nucleoside analogues Non-nucleoside analogues Nevirapine, Delavirdine, TMC-120, TMC-125

17 from Goff, Fields Virology, 4th edition 1.3’-end processing (cytoplasm) 2.Cleavage of cell DNA (nucleus) 3.Strand-transfer 4.Gap filling -5-bp direct repeat of cellular DNA - dinucleotides: 5’-TG; 3’-CA

18 Model of HIV genomic packaging From M. F. Summers

19 HAART Highly Active Anti-Retroviral Therapy (HAART) consists of 3 or more highly potent anti-HIV drugs, commonly reverse transcriptase inhibitors and protease inhibitors. a single drug therapy may be successful for a while, but because HIV changes to avoid detection, drug- resistant strains will often arise in the patient. The chances of a HIV genome mutating such that it can resist three separate drug treatments at once, however, is so small that the pressure of this therapy prevents the emergence of resistant strains




23 HIV reservoirs CD4 T cells - post-integration latency mostly in memory CD4 T cells - no active or low level active viral replication - rapidly generate viruses upon stimulation Macrophages - tissue and brain macrophages, monocytes - resist to HIV mediated cell killing - actively generating virus in the body for a long period of time

24 Current Strategy to activate latent viral reservoirs HDAC inhibitors Histon Deacetylase Inhibitors

25 Limitations of re-activation strategy 1)Viral reservoirs in the body is not currently well- identified and understood 2)Not every latent virus can be re-activated by a single method 3)Reactivation does not lead to the elimination of latent cells

26 A “trojan horse” strategy to identify and eliminate HIV positive cells

27 The making of the “trojan horse” 5’ LTR rev tat gag pol env nef vpu vif 3’ LTR D1 A5 D4 A7 X X X X X X X X vpr X

28 HIV-1 Rev-dependent gene expression gp160, Pr55 tat, rev, nef env, vif, vpu, vpr gag-pol Rev Tat, Rev, Nef gp160, Pr55

29 mRNA The Rev-dependent lentiviral vector: pNL-GFP-RRE Rev

30 Procedure for generating lentiviral particles pMD.G(VSV) pCMV∆R8.2 pNL-GFP-RRE 293T cells

31 1. HIV-1(AD8) infection of macrophages 2. Super-infection with vNL-GFP-RRE +


33 High specificity of the Rev-dependent vector

34 NIH AIDS Research & Reference Reagent Program: Cat # 11466 Email: Phone: 703-993-4299

35 Rev-dependent vectors carrying toxins and pro-apoptotic genes for targeting HIV-positive cells Anthrolysin O Diphtheria toxin A chain Human TRAF-6

36 - secreted by Bacillus anthracis - pore-forming, cholesterol-dependent cytolysin - lethal to to human primary monocytes, macrophages - cytotoxic activity is sensitive to the inhibition by cholesterol or serum Anthrolysin O (AnlO)

37 Diphtheria toxin EF2 + NAD + ADPR-EF2 + nicotinamide + H + DT - DT is an ADP ribosylating enzyme - the most studied bacterial toxin - ADP ribosylation occurs at one modified histidine in EF2 - highly toxic, one molecule can kill a cell - multiple previous animal and human clinical trials using DT-A for cancer therapy and immuno-therapy to kill T cells Protein Synthesis Time Diphtheria Toxin

38 - endogenous human gene - low level expression is tolerated and my help viral gene expression - over-expression trigger’s apoptosis - may not be as effective as bacterial toxins - safer to use than bacterial toxins Tumor necrosis factor-associated factor 6 (TRAF6)

39 Killing efficiency: DT = 100%, TRAF6 = 86%, AlnO = 55%

40 DT-A mutants with reduced cytotoxicity DT-A = 100% E18S = 96% E148D = 93% G128D = 65% DT∆N = 52%

41 Difficulties in assembly of lentiviral particles carrying toxins pMD.G(VSV) pCMV∆R8.2 pNL-GFP-RRE-(SA) 293T cells


43 Cloning and Mutagenesis of human EF-2 gene *GGA CGA Gly Arg

44 5H7, 46% CB2, 28% AB1, 24% 4H10, 14% 5E12, 9% 293T, 0% From about 100 clones 5 were DT-resistant

45 293T 5H7 pNL-DT-GFP-RRE pNL-DT(R)-GFP-RRE 0.0% 54% 64% 43% 0% DT-resistance: 84%

46 Resistance of 293T cells to TRAF-6 HeLa GFP TRAF-6 0.0% 53% 24% 0.5% 7.6% 293T 0.0% 39% 25% Cell control


48 Proof-of-concept: killing of HIV-positive macrophages in vitro

49 Proof-of-concept: killing of HIV-positive T cells in vitro

50 Limitations of the vector 1.Lack of selective entry 4. Toxin contamination of particles 2. Lack of ability to target resting CD4 T cells 5. Are they really safe ? 3. Integration-mediated mutagenesis

51 - need safety test in animals Are these toxin particles really safe to inject ?

52 New York to DC

53 Acknowledgements NIAID: AI069981, AI081568 NINDS: NS051130 NYCDC AIDS ride GMU: Jessica Young Zhong-wei Tang Yangfan Zheng Dongyang Yu Jeremy Kelly Mark Spear Quan Yu Barney Bishop Sub Iyer Vladimir Karginov Serguei Popov Taissia Popova NIH: Jon Marsh David Neville Harvard Medical School: Zhirui Wang Zhong wei

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