传染病学Chapter32 反转录病毒.ppt

Chapter 32Retrovirus Retroviridae include 7 genera:AlpharetrovirusBetaretrovirusGammaretrovirusDeltaretrovirus: HTLV (Human T Lymphotropic Virus)EpsilonretrovirusLentivirus: HIV (Human immunodeficiency Virus)Spumavirus: Section 1Human immunodeficiency virus ( HIV ) I have it! – it happened on Friday, 4 February 1983, at 5:45 p.m. World AIDS prevalence 2008 AIDS prevalence in China 2006 HIV Pathogen of AIDS ( Acquired Immunodeficiency Syndrome ).HIV-1 is found worldwide, HIV-2 is found primarily in West Africa.9 Ⅰ.Biological properties1. Morphology: Spherical, enveloped, spikes.2. Structure: Core: 2 copies of +ssRNA ( dimmer ); reverse transcriptase; integrase, protease, RNase HCapsid protein: P24Matrix protein: P17Envelope: gp41, gp12010 11 gp41: mediates fusion of the viral envelope with the cell membrane, facilitates the virion to enter the cell.gp120: * be associated with adsorption (binding site for CD4 molecule of T cells). * be able to stimulate the production of neutralizing antibodies. * easy variation.12 3.Genes:Structural genesRegulatory genesLTRStructural genes: gag: coding for capsid proteins ( p17, p24, p7 ) pol: coding for protease, reverse transcriptase etc. env: coding for gp120, gp41.13 4.Resistance: weak,100℃ 20min inactivated frozen blood 68 ℃ 72h5.Replication: Adsorption : gp120 binds to CD4 molecule of T cells the necessary co-receptors? for HIV-1 entry: CXCR4 for T-cell line (T)-tropic strains CCR5 for macrophage (M)-tropic strains14 Penetration: membrane fusionUncoating:Biosythesis: RNA---cDNA--- RNA:DNA hybrid molecule ---dsDNA---integrated into host DNA (provirus) ---stay latent ---enter a productive cycleAssembly, maturation and release: budding15 16 Ⅱ.Pathogenesis & immunity1.Infectious source: patients (symptomatic), infectious people (anti-HIV(+), asymptomatic).2.Transmission pathway: 1) By Sexual contact; 2) By blood o