Basic Rapporteur 2005

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RAPPORTEUR SESSION TRACK A: BASIC SCIENCES 14th Annual Canadian Conference on HIV/AIDS Research May 12-15, 2005 Vancouver

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Basic Sciences track: - 21 oral presentations 8 posters - U. Ottawa/OHRI: 9 - U. Manitoba: 6 - McGill: 4 - U. Toronto: 3 - SFU: 2 - BC Centre for Excellence in HIV/AIDS: 1 - U. Montreal: 1 - Gilead Sciences Inc.: 1 - UCLA: 2

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Alan Cochrane, University of Toronto.

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Alan Cochrane, University of Toronto.

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g U1 HIV-1 #5 4 3 2 1 0 g U1 HIV-1 #1 0 1 2 3 4 gp120 p55 p24 -tubulin 9 8 7 6 5 4 3 2 1 175 kDa 62 48 25 62 48 U1-mediated suppression of HIV-1 protein synthesis Untransfected U1 U16A U1 CAT Alan Cochrane, University of Toronto.

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Inhibition of infection by soluble mimics of gp120-binding glycolipids (AdamantylGSLs) Concentration (µM) HIV-1IIIB Infection (P24 pg/ml) Concentration (µM) HIV-1IIIB Infection (P24 pg/ml) Concentration (µM) HIV-1IIIB Infection (P24 pg/ml) AdaGb3 AdaGC AdaSGC Nicole Lund, University of Toronto. Target both X4 and R5 viruses

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- Cytokines of the common gamma chain regulate memory cell homeostasis IL-2, IL-7, IL-15 (Schluns, K. S., Nat. Rev. Immunol. 3:269-79, 2003). - Expression of IL-7R is increased on memory cells (Kaech, S. M.,. Nat. Immunol. 4:1191-8, 2003). - Increased levels of IL-7 are associated with CD4 T-cell lymphopenia in HIV disease (Napolitano, L.A., Nat. Med. 7:73-9, 2001). - In HIV, there is a downregulation of IL-7Ra on both CD4+ and CD8+ T cells (MacPherson PA, J Acquir Immune Defic Syndr 2001;28:454-7, Carini C, Eur J Immunol 1994;24:2927-34, Vingerhoets J, Immunol Lett 1998;61:53-61, Mussini C, Aids 2002;16:1609-16, Marchetti G, Antivir Ther 2004;9:447-52, Paiardini M, J. Immunol 2005;174:2900-9. IL-7R Slide courtesy of Sandra Koesters, University of Manitoba.

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- CD4+ T cells from HIV+ individuals with a more advanced stage of progression, have lower IL-7Ra levels. - The IL-7Ra reduction is most evident in the central memory compartment. Sandra Koesters, University of Manitoba.

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Highly active antiretroviral therapy (HAART)  in HIV viral load (VL) to undetectable level (<50 copies/ml)  in CD4+ cell count Over time some patients develop a pattern of  in CD4+ cell count despite relatively high-levels () of VL   CD4+/VL discordant immune responses to HAART Clinical point of view  in CD4+ cell: clinical benefit Continuing a failing regimen (VL > 50 copies/ml):  cross-resistance to unused drugs, thereby limiting future therapeutic options A better understanding of discordant CD4+/VL responses may help define proper clinical management M-R Boulassel, Mc Gill University

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Expression of surface markers on CD4+ naïve cells CD4+ naïve cells expressing IL-7R (CD127) were higher in DR than in ST M-R Boulassel, Mc Gill University

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IL-7 Receptor is Down-Regulated on CD8 Cells from HIV Infected Individuals. Paul MacPherson, Ottawa Health Research Institute.

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HIV Tat protein specifically down regulates CD127 on CD8 T-cells Tat does not affect expression of : CD2, CD3, CD8, CD28, CD45RA, CD45RO, CD56, CD62L Time (hours) Paul MacPherson, Ottawa Health Research Institute.

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HIV Tat does not down regulate CD132 (the common -chain) on CD8 T-cells Paul MacPherson, Ottawa Health Research Institute.

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Tat prevents IL-7 mediated up regulation of perforin and inhibits CD8 T-cell proliferation following stimulation. By down regulating CD127, Tat may prevent complete differentiation of naive cells to the effector phenotype. Impaired cell mediated immunity. Paul MacPherson, Ottawa Health Research Institute. Role of Tat in CD127 dowregulation in CD4+ T cells?

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IL-15 decreases CD127 surface expression on CD8+ T-cells. IL-4 decreases CD127 surface expression on CD8+ T-cells. Angela Crawley, Ottawa Health Research Institute.

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IgG1 b12 footprint in gp120, according to the docked model by Saphire et al., Science 293:1155, 2001. The CD4-binding site is shaded in pink. Neutralizing MAb b12

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Results MRVKEKYQHL WRWGWKWGTM LLGILMICSA TEKLWVTVYY GVPVWKEATT TLFCASDAKA YDTEVHNVWA THACVPTDPN PQEVVLVNVT ENFNMWKNDM VEQMHEDIIS LWDQSLKPCV KLTPLCVSLK CTDLGNATNT NSSNTNSSSG EMMMEKGEIK NCSFNISTSI RGKVQKEYAF FYKLDIIPID NDTTSVTITS CNTSVITQAC PKVSFEPIPI HYCAPAGFAI LKCNNKTFNG TGPCTNVSTV QCTHGIRPVV STQLLLNGSL AEEEVVIRSA NFTDNAKTII VQLNQSVEIN CTRPNNNTRK SIRIQRGPGR AFVTIGKIGN MRQAHCNISR AKWNATLKQI ASKLREQFGN NKTIIFKQSS GGDPEIVTHS FNCGGEFFYC NSTQLFNSTW FNSTWSTEGS NNTEGSDTIT LPCRIKQFIN MWQEVGKAMY APPISGQIRC SSNITGLLLT RDGGNNNNGS EIFRPGGGDM RDNWRSELYK YKVVKIEPLG VAPTKAKRRV VQREKR Nature (1998)393:648-659 CD4 binding site Science (2001)293:1155-9 b12 binding site Mass spectrometry epitope Jillian Waruk, University of Manitoba.

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Neutralization assay Primary isolates? Jillian Waruk, University of Manitoba.

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A. C. B. (A) Architecture of the 2G12 Fab dimer. The light chains are shown in cyan and the heavy chains in red and blue. (B) Interactions of the 2G12 Fab dimer with Man9GlcNAc2. (C) Chemical structure of Man9GlcNAc2. Calarese et al., Science 300:2065, 2003. Neutralizing MAb 2G12

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Molecular surface representation of a 2G12 monomer showing antibody areas in contact with 2G12.1 peptide (cyan) and Man1-2Man (pink), residues that contact both ligands are in yellow. The backbone of 2G12.1 peptide is shown in green. (A) Side view; (B) Top view. The antibody light chain is shaded in dark gray, the heavy chain in lighter gray. Tyr L94, TyrH57 and the primary carbohydrate-binding site (PCBS) are indicated. Contacts with Man1-2Man taken from Calarese et al., Science 300:2065, 2003. Contacts with 2G12.1 peptide are from this work. A. B. L94 H57 PCBS

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Xin Wang, Simon Fraser University

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Vpr R77Q mutation: associated with impaired apoptosis ability and long-term nonprogression? - The apoptosis-inducing function of HIV Vpr maps to a conserved (HFSRIG)CR(HSRIG) amino acid motif at its C-terminal end - Evidence published by Lum et al (J. Clin. Invest. 2003) suggested that the VprR77Q mutation was associated with Impaired ability of HIV Vpr to induce apoptosis in vitro Long-term nonprogressive infection in untreated infection (sequences and clinical information derived from LANL Database) Zabrina Brumme, B.C. Centre for Excellence in HIV/AIDS vpr genotyping of 728 individuals (before HAART)

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1. Cross-sectional analysis of our cohort at baseline (pre-therapy) do not support an association between VprR77Q and nonprogressive infection in untreated individuals. No observed correlation between Vpr R77Q and clinical markers of HIV disease severity including CD4 and pVL 2. Vpr R77Q is not a relevant predictor of clinical response to therapy or survival following initiation of HAART 3. Polymorphisms at HIV Vpr codon 77 may be correlated with differences in virus clade Conclusions Zabrina Brumme, B.C. Centre for Excellence in HIV/AIDS

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Presumably, CTL drove different escape mutations between twins. Similarity of HIV-1-specific CTL targeting but differences in epitopes Otto Yang, UCLA

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Some lessons from the twins study Escape in vivo is subject to stochastic factors (probably TCR differences). The interaction of HIV-1 and CTL in vivo is thus somewhat unpredictable. Otto Yang, UCLA