10/01/57. Overview. Goal. Conclusions. Immunity to infection. How to classify immunity by time?? (stages, cells involved in immune responses)

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1 Overview Immunity to infection Animal Immunology Vibuntita chankitisakul, D.V.M.,Ph.D. Immune system Bacteria infection Virus infection Fungus infection Goal How to classify immunity by time?? (stages, cells involved in immune responses) To understand basic principles of defense against infections induced by: Bacteria - extracellular - intracellular Virus Fungus Parasites What are the mechanisms of HMI and CMI?? Conclusions against_disease/index.htm 1

2 Make sure you understand these following words Innate immunity Physical barriers Chemical barriers Phagocyte Neutrophils Eosinophil Basophils Macrophage Monocytes Acquired immunity Cellular immunity Humoral immunity T, B lymphocytes Antibody NK cells Complements Cytokine Interferon Immunity response to microbial infection Microbes Site of infection microbiologists deal with four fundamental kinds of microbial infectious agents bacteria fungus viruses parasites helminthes (worms) protozoa (single-celled) (intracellular) 2

3 Site of infection Extracellular Intracellular Location of infectious agents in host tissue is of the essence for development and differentiation of immune responses Microbial type Extracellular Intracellular Bacterium E. coli, Salmonella Mycobacteria, Listeria Organisms Bacteria, protozoa, fungus, worms Viruses, bacteria, protozoa,fungus Fungus Candida Histoplasma Parasite Helminths (worms) Plasmodium Protective immunity Antibodies, Complement, Phagocytosis, Neutralization Cytotoxic T-cells, NK cells Virus None All Bacterial infection Bacterial infection 1. Extracellular bacteria are capable of replicating outside host cells Inflammation Toxins (endotoxin, extoxin) 2. Intracellular bacteria ability to survive and even to replicate within phagocytes Tuberculosis 1) Innate immunity Complement activation Activation of phagocytes and inflammation 2) Acquired immunity Humoral immunity is a major protective immune response Neutralization of toxins Complement activation Opsonization Phagocytes 3

4 Acquired immunity Acquired immunity ability to survive from antibodies Intracellular bac. Innate and adaptive immunity to intracellular bacteria 1. Innate immunity Phagocytes and NK cells Bacteria stimulate Macrophage to release Cytokines, then stimulate NK cells to release IFN to activate macrophage (activated macrophage) CD8 CD4 2) Adaptive immunity CMI Intracellular bac. Virus infection 4

5 Viruses Viruses do not have ribosomes and cannot make their own protein After the virus attaches to the host cell s membrane, it injects its genetic material which directs synthesis of viral proteins Virus infection Intracellular microorganisms Based on Harvard Medical School Family Health Guide Fungus infection Fungus infection extracellular and intracellular (phagocyte) fungi Innate immunity Neutrophils and macrophages Adaptive immunity CMI (same as intracellular bacteria) Antibody important for diagnosis only (not for eradication) 5

6 Complex eukaryotic organisms Complex life cycles protozoa (unicellular) intra- & extracellular agents helmints (multicellular worms) extracellular agents Innate immunity Mostly resistant complement and phagocytosis (protozoa) eosinophil and macrophages (worms) Adaptive immunity Protozoa (intracellular) CMI Immunity against worms (T H 2 response) Worms (extracellular) Antibody (IgE) + Eosinophil Immunity against helmints (function of eosinophils) 6