Innate Immunity Overview Flashcards
How do phagocytic cells identify pathogens?
They recognize pathogen-associated molecular patterns (PAMPS) and damaged/necrotic self, damage-associated molecular patterns (DAMPS)
What are some examples of Pattern Regonition Receptor?
Toll-like receptors, Lectin, NOD-like receptor, RIG-like receptor
Where can Toll-like receptors be found?
On the cell membrane, in endosomes, or in the cytoplasm?
What is TL-1, 2 responsible for?
Recognizes several bacterial and parasitic glycolipids and peptidoglycans
What is TLR3, TLR7, and TLR8 responsible for?
Responsible for viral single-stranded and double-stranded RNAs. Since this acts on RNA, the TLR is in an endosome
What is TLR4 responsible for?
Recognizing bacterial LPS (endotoxin)
What is TLR5 responsible for?
Regonizing bacterial flagellar protein called flagellin
What is TLR9 responsible for?
Recognizing unmehtylated CpG DNA that is abundant in microbial genomes. Found in endosomes
What is the interferon system and what is it used for?
Component of innate immune defense which is used against intracellular viruses
What are the components of the Innate Immunity?
Host barriers; Enzymes in epithelial and phagocytic cells; Inflammation-related serum proteins; antimicrobial peptides on the surfaces of t cells within phagocyte granules; phagocytic cells identifying PAMPS and DAMPS; cell receptors that sense micro-organisms and signal a defensive response; complement; acute inflammation; pro-inflammatory cytokines, NK cells, mast cells and other granulocytic cells
Neutrophil cell type and function?
WBC Granulocyte; Engulf bacteria and fungia, oxidative burst
Monocyte/Macrophage cell type and function?
WBC Mononuclear; Engulf bacteria, fungi, and cellular debris, produce cytokines, antigen processing
Eosinophil cell type and function?
WBC Granulocyte; Associated with allergic response and parasitic infection (helminthic)
Basophil cell type and function?
WBC Granulocyte; Associated with hypersensitivity and release histamine
Mast cell type and function?
Bone marrow derived cell; Granules contain vasoactive amines like histamine, proteases kill bacteria
Natural killer cell type and function?
WBC Lymphocyte; Recognizes stressed or infected cells and kills them by secreting macrophage-activating cytokine INF-gamma
Dendritic cell cell type and function?
Bone marrow derived; Phagocytosis, APC, initiation of T-cell responses. Immunosurveillance. They are less phagocytic than neutrophils and macrophages and do more consuming through endocytosis
These cells secrete granules that contain granyzme and performin and cell surface receptors for IgG
Natural killer cells
How are follicular dendritic cells different than normal dendritic cells?
Follicular dendritic cells are more adept at trapping antigens and presenting them to B cells while Dendtritic cells are very efficient at present antigen to T cells
What are some examples of Pattern Associated Molecular Patterns?
Bacterial peptidoglycan, Lipoportein, LPS, Bacterial flagellin, lipotechoic acid, viral envelope proteins
Where is interleukin-6 found and what are its targets?
Found in macrophages, endothelial cells, T-cells; Targets are the liver for synthesis of acute-phase proteins and B-cells for proliferation of antibody-producing cells
Where is Interleukin-1 found and what are its targets?
Found from macrophages, endothelial cells, and some epithelial cells; Recruits neutrophils. Targets are endothelial cells for activation of inflammation and coagulation. hypothalamus during fever, liver for synthesis of acute phase proteins, T-cells for Th17 deifferentiation
What are acute phase reactants? What is the chief stimulator in the production of most acute-phase proteins?
During the acute phase response, usual levels of various proteins by homeostatic mechanisms change. These changes are thought to contribute to host defense and other adaptive capabilities. These proteins are Acute Phase Reactants; They are largely stimulated by Interleukin-6. The other implicated cytokines influence subgroups of acute-phase proteins
What might change the concentration of acute-phase proteins?
Infection, trauma, burns, surgery, tissue infarction, various immunologically medicated inflammatory conditions, advanced cancer
Where are the majority of these acute-phase proteins produced and how are they defined?
They are produced by hepatocytes and are labeled as acute-phase proteins if their levels increase/diminish by 25% during inflammatory disorders.
What are some examples of acute-phase reactants?
1) C-reactive protein 2) Serum amyloid A (SAA) 3) Complement components 4) Haptoglobin and hemopexin 5) Hepcidin 6) Fibrinogen
Describe the role of the APR, C-reactive protein
C-reactive protein: Promote recognition and elimination of pathogens and enhance clearance of necrotic and apoptotic cells. Pro-inflammatory effects include activation of complement system and induction in monocytes of inflammatory cytokines
Describe the role of the APR, Serum amyloid A (SAA)
Serum amyloid A (SAA): Proteins influence cholesterol metabolism during inflammatory states
Describe the role of APR, complement components
Complement components: serve pro-inflammatory roles, including chemotaxis, plasma protein exudation at sites of inflammation, and opsonization of infection agents and damaged cells
Describe the role of APR, Haptoglobin and hemopexin
Haptoglobin and hemopexin: Antioxidants that protect against reactive oxygen specieis by removing iron-containing cell-free hemoglobin and heme, respectively from the circulation
Describe the role of the APR, Hepcidin
Hepcidin: Can contribute to decreases in serum iron by release intestinal iron absorption and impairing the release of Iron from macrophages. Bacteria love iron, so if you decrease it, they won’t replicate as much.
Describe the role of the APR, Fibrinogen
Fibrinogen: Influences would healing. Causes endothelial cell adhesion, spreading, and proliferation, which is critical to repair
