* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Week 2 Immunology
Immunocontraception wikipedia , lookup
Herd immunity wikipedia , lookup
Complement system wikipedia , lookup
Major histocompatibility complex wikipedia , lookup
Sociality and disease transmission wikipedia , lookup
Gluten immunochemistry wikipedia , lookup
Lymphopoiesis wikipedia , lookup
Social immunity wikipedia , lookup
Monoclonal antibody wikipedia , lookup
Hygiene hypothesis wikipedia , lookup
Molecular mimicry wikipedia , lookup
DNA vaccination wikipedia , lookup
Immune system wikipedia , lookup
Adoptive cell transfer wikipedia , lookup
Adaptive immune system wikipedia , lookup
Cancer immunotherapy wikipedia , lookup
Innate immune system wikipedia , lookup
X-linked severe combined immunodeficiency wikipedia , lookup
Polyclonal B cell response wikipedia , lookup
Week 2 Immunology Dr. Lydia Medeiros Food Safety and High-Risk Groups Vocabulary of the Immune System Handout #1 Food Safety and High-Risk Groups The Immune System • Innate or Natural Immunity (vertebrates/invertebrates) – Nonspecific response – Immediate response – Short-term response • Adaptive or Acquired Immunity (vertebrates) – Specific response – Slow response – Long-term response Innate Immunity • • • • • • Skin Mucosal secretions Intestinal pH and digestive enzymes Peyer’s Patch in intestine (M cells) Reticuloendothelial System Involves Natural Killer cells, Complement and Phagocytic cells (neutrophils or macrophages) The Reticuloendothelial System • Blood and tissue phagocytic cells (neutrophils and macrophages) • Lymphoid tissue • Liver (Kupffer cells) • Spleen (red pulp) • Bone marrow • Lung, lining of the GI tract, urogenital tract Destruction of Bacteria by Phagocytosis and Complement Handout #2 Food Safety and High-Risk Groups Cells of the Immune System Handout #3 Food Safety and High-Risk Groups Cells of the Immune System • B-cells – Derived from stem cells in the bone marrow – Late stage or mature B-cells released to circulation (maturity completed in spleen) – Naïve B-cells encounter antigen via antigen presenting cells or direct contact – Immune reactions involve lymphatic system, lymph nodes, and spleen (white pulp) Cells of the Immune System • T-Cells – – – – Derived from stem cells in bone marrow Immature T-cells transport to the thymus Selectivity against self occurs in thymus Only about 5% of nascent T-cells survive maturation in the thymus – Responds to MHC class I and class II complexes in periphery, especially lymphatic system and lymph nodes Overview Summary • First line of defense – Mechanical barriers – Chemical barriers • Second line of defense – Inflammation response – Phagocytosis • Third line of defense – Specific immune responses – Natural Killer Cells Questions and Answers Ohio Colorado Washington State Food Safety and High-Risk Groups Adaptive Immunity Adaptive Immunity Humoral Immunity B-cell and antibody mediated response Food Safety and High-Risk Groups Cell Mediated Immunity T-cell response Adaptive Immunity • Phagocytic cells (neutophils or macrophages) • Thymus and lymphoid tissues • B-cells and T-cells Food Safety and High-Risk Groups Adaptive Immunity Antibody A protein that is produced as a result of the introduction of an antigen and has the ability to combine with the antigen that stimulated its production. Food Safety and High-Risk Groups Adaptive Immunity Major Histocompatibility Complex (MHC) A cluster of genes located in close proximity that determine histocompatibility antigens from members of a species. (eg. recognition of self versus non-self). Food Safety and High-Risk Groups Adaptive Immunity Cytokine A factor such as a lymphokine or monokine produced by cells that affect other cells (eg. lymphocytes and macrophages) and have multiple immunomodulating functions. Cytokines include interleukins and interferons. Food Safety and High-Risk Groups Adaptive Immunity • B-cells – – – – naïve cells have not encountered antigen antibody on cell surface binds antigen antigen presenting cells predominately require signal from T-cell for activation – after activation, plasma cells produce and secrete antibodies – some B-cells become memory cells Adaptive Immunity • T-cells – CD4 T-cells (Helper – TH1 or TH2) • Recognized MHC class II complexes • TH1 activates macrophages • TH2 activates B-cells – CD8 T-cells (Cytotoxic or Killer T-cells) • Recognizes MHC class I complexes • Lyses infected cells The Humoral Immune Response Cytokine release (IL-4 and 5) from helper T cell activates B cell CD4 Helper T-cell (TH2 type) Plasma cell T-cell receptor combines with MHC II complex Memory B-cell B-cell proliferation Pathogen Lymph Node B-cell Antigen presenting cell MHC II complex formed The Cell-Mediated Immune Response CD4 Helper T-cell (TH1 type) Cytokine release and interaction with CD8 cells Antigen Presenting Cell Pathogen CD8 Cytotoxic T-cell Questions and Answers Ohio Colorado Washington State Food Safety and High-Risk Groups How do foodborne pathogens invade the human body? Food Safety and High-Risk Groups Viral Infections Norovirus and Hepatitis A CD8 Cytoxic Tcell responds to MHC class I complex Virus Virus produces protein ﻉ Natural Killer cell Protein/MHC class I complex forms Antigen Presenting Cell Parasitic Infection Toxoplasmosis gondii Tissue cell Parasite Parasitic Infection Toxoplasmosis gondii Cryptosporidium parvum ??? Cytokine release and interaction with CD8 cells Macrophage CD4 Helper T-cell (TH1 type) Parasite CD8 Cytotoxic T-cell Bacterial Intoxications (Exotoxin) Staphylococcus aureus Bacterial exotoxin acts as Superantigen Massive Ineffective cytokine CD4release T-cell Ineffective CD4 T-cell Systemic Toxicity – Virulence factor CD4 Supressed Immune Response T-cell Human Host Becomes Sicker Antigen Presenting Cell Ineffective CD4 T-cell Ineffective Massive CD4 T-cell cytokine release Bacterial Infection Listeria monocytogenes Macrophage Macrophage Listeria infects another macrophage Listeria No Immune Response Bacterial Infection Listeria, Campylobacter, V. parahaemolyticus, Yersinia CD4 Helper T-cell (TH1 type) Cytokine release and interaction with CD8 cells Antigen Presenting Cell Pathogen CD8 Cytotoxic T-cell Toxin-Mediated Infections Salmonella, Shigella, E. coli O157, C. perfringens, B. cereus • Toxin – Produced systemically or intra-luminally – Toxin neutralized by antibodies and complement • Infective cells – Neutralized by immune response Toxin-mediated Infection Bacteria grow Produce toxin Toxin opsonized by antibody and complement Phagocytosis by APC Questions and Answers Ohio Colorado Washington State Food Safety and High-Risk Groups The Immune System and Groups at High Risk for Foodborne Illness Infants and Young Children Pregnancy Seniors Immune Compromised Food Safety and High-Risk Groups Infants and Young Children • Immune defect – Immature immune system response – Lower infective dose Pregnancy • Immune Defect – Hormonal suppression of cell-mediated immunity – Switch from TH1 or TH2 T-cell type that favors antibody response – Listeria and Toxoplasmosis response specific for TH1 type T-cells Listeria : Mode of Infection Pregnancy Helper T-cell (Th-2 type) Humoral Immune Response (Antibodies Produced) Listeria Listeria infects another macrophage The Elderly • Immune Defect – Decrease stomach acidity naturally – Increased use of anti-acid, anti-inflammatory or steroid medications – Decline in immune system response due to aging – Nutritional influence on immune response – Greater chance for exacerbating acute or chronic disease Immune Compromised Status Pharmacological Immune defect • Cancer - Loss of immune response efficiency due to disease or medical therapy • Bone marrow transplant – Major reduction of immune system function due to absence and function of bone marrow • Solid organ transplant – Mild suppression due to lifelong use of immune suppressant drugs to prevent graft rejection. Questions and Answers Ohio Colorado Washington State Food Safety and High-Risk Groups