Retrovirus Retroviridae Retrovirus HTLV (human T-cell lymphotropic virus) Lentivirus HIV Common Properties Spherical, 100nm; enveloped Two copies of +ssRNA Reverse transcriptase and Integrase Replication: DNA intermediate Structure genes: gag, pol, env genes Tissue tropism: determinated by receptor Budding Human Immunodeficiency Virus (HIV) Clinical case A 32-year-old ex-heroin addict had a mononucleosis-like illness for 2 weeks, occasional nigh sweats and fever for 3 years and then presented with thrush, cytomegalovirus retinitis, and pneumocystis pneumonia. His CD4 T cell count is less than 200/ul. HIV CD4+ T helper lymphocyte AIDS (acquired immunodeficiency disease syndrome) Fatal 40 million 1.5 million (2004); 10 million (2010) Biological Properties Structure Biological Properties Replication Receptor: CD4 antigen Main host cell: CD4+ T4 helper cells Co-receptor: CCR5, CXCR4 Biological Properties Typing and Variation HIV-1 HIV-2 High variation gp120 Pathogenicity Source: human Transmission Sexual transmission Blood transmission Vertical transmission Route not involved in transmission: close personal contact Clinical Findings Acute infection Clinical latency AIDS related complex AIDS Kaposi's sarcoma Opportunistic infection Pathogenesis Virus tropism for CD4+ T cells and macrophages Reduction in the number of CD4+ T cells Pathogenesis CD4+ T cells and memory cells Lytic infection of CD4 T cells Syncytia formation CTL effect on the viral proteins on the cell surface Free gp120-CD4 Ag Auto-immune defense-gp120 Apoptosis Cellular latency: T4 cells CD8+ cells: apoptosis Microbiological Diagnosis Serology Genomics Viral particles Treatment and Prevention Prevention Education Vaccine: no effective in practice Treatment Highly active anti-retroviral therapy (HAART)