Tabbara - Immunity to Viral Infection.ppt

Master in Laboratory Medicine First Semester Module IV Host-Parasite Interactions Immunity to Viral Infection Dr. Khaled S. Tabbara Patterns of Viral Infections The Molecular Basis of Interferon Action Role of Macrophages in viral infections Opsonization of viruses – Antibody – Complement Macrophage...

Master in Laboratory Medicine First Semester Module IV Host-Parasite Interactions Immunity to Viral Infection Dr. Khaled S. Tabbara Patterns of Viral Infections The Molecular Basis of Interferon Action Role of Macrophages in viral infections Opsonization of viruses – Antibody – Complement Macrophage Phagocytosis of opsonized viruses ADAPTIVE RESPONSES Effector Mechanisms against Virus and Virus-infected cells Cytotoxic T Lymphocytes (CD8+ T Lymphocytes) Are the major defense against Viral infections MHC Antigen Distribution Class I - All nucleated cells Class II – Restricted to mononuclear cells (Lymphocytes & Macrophages) Structure of MHC Class I & II Molecules 3D structure of MHC Class I molecule MHC – peptide interaction MHC Restriction in Sensitization of T Lymphocytes Cell Killing in Viral infection Cytotoxic T cells recognize and bind to infected body cells and destroy them 1 Cytotoxic T cell binds to infected cell Foreign antigen 2 Perforin makes holes in infected cell’s membrane 3 Infected cell is destroyedby lysis Hole forming INFECTED CELL Perforin molecule Cytotoxic T cell Figure 24.13C