COMPONENTS OF INNATE IMMUNITY INNATE IMMUNITY Inflammation (and hypersensitivity) cellular reaction humoral reaction inflammatory mediators Phagocytosis antimicrobial substances reactive intermediates of oxygen and nitrogen Complement activity lytic activity other biological activities Collectins and other antimicrobial peptides Heat shock proteins Natural cytotoxicity Interferons NEUTROPHILS PHAGOCYTING CELLS the most important phagocytes cells of acute phase of inflammation three types of granules with lytic enzymes marked oxidative burst (intermediates of oxygen and chlorine) they are not able to present antigen! MACROPHAGES important phagocytic cells less microbicide products marked activity of nitric intermediates in activated mφ production of TNF and other cytokines regulative and effector function ability of antigen presentation EOSINOPHILS cells of inflammatory reaction, mainly in hypersensitivity of type1 Neutrophil granulocyte small to large cells with bar-shaped to segmented nucleus, has a finely granular cytoplasm short-lived, in blood circulates approx. 6 hours, in tissues 2 days marked phagocytosis the main population of early antibacterial defence early inflammation
Eosinophil granulocyte Bazophil granulocyte mast cell phagocytosis as well as other inflammatory functiones hypersenzitivity of 1 st type key role in defence against multicellular parazites (worms) releases different proteins major basic protein, cationic protein, peroxidase, neurotoxin into the surrounding fluid containe granulas with histamine and other mediators high-affinity receptor for Fc fragment of IgE. bazophils circulate in blood, mast cells are in tissues mast cells are the key cells in inflammation associated with hypersenzitivity of 1 st type Monocyte macrophage monocyte in blood large cell with kidney-shaped nucleus shortly circulates in blood direct precursor of macrophage macrophage in tissues, long-lived cell high morphological heterogenity different names in different tissues cell of chronic phase of inflammation phagocyting cell with ability to present antigen high production of cytokines Dendritic cells long, filamentous cytoplasmic processes dendrites Birbeck granules in cytoplasm Langerhans cells in epidermis Interdigitating DC in T cell areas of lymphoid organs Follicular DC in B cell areas of lymphoid organs the major antigen-presenting cells expressing of MHC class II Poor phagocytosis
MECHANISMS OF NESPECIFIC RECOGNITION RECEPTORS OF RECOGNITION Tizard pp. 11-12 MECHANISMS OF NONSPECIFIC RECOGNITION Recognition of microbial components patogen-associated molecular pattern - PAMP LPS, peptidoglycans, lectins, glucan receptors for PAMP on cells toll-like receptors activation of C3 convertase by microbial surface trigger alternative pathway Recognition of non self cells Lack of MHC I x KIR receptors on NK cells down expression of CD47 on old cells trigger apoptosis and phagocytosis Tizard 11-12 RECEPTORS OF NONSPECIFIC RECOGNITION TLR 1-10 CD14 Mannose binding receptor Galactose binding receptor Scavenger receptor - SR
TLR TLR 1, TLR 2 TOLL-LIKE RECEPTORS recognized structure lipopeptids (gramnegativne bacteria), lipoteichic acid (grampositive bacteria), lipoarabinomanan (mycobacteria) zymosan (fungi) RECOGNITION BEFORE PHAGOCYTOSIS Receptors of nonspecific recognition Receptors for immunoglobulins (FcR) TLR 3 TLR 4 (+ CD14) TLR 5 TLR 6, TLR 2 TLR 7, TLR 8 TLR 9 ds RNA (viruses) lipopolysaccharides (gramnegativne bacteria) flagellin (bacteria) bacterial lipids ss RNA (viruses), imiquimod unmetylated CpG DNA (bacteria) Receptors for complement fragments (CR) OPSONIZATION Fc AND C RECEPTORS OPSONIZATION Fc receptors FcγRI (CD64) high-affinity receptor of monocytes FcγRII (CD32) low-affinity receptor of monocytes and neutrophils FcγRIII (CD16) low-affinity receptor of NK cells (and neutrophils) FcµR receptor for IgM, FcεRI a II receptors for IgE binding on masts cells Complement receptors CR1 (CD35) receptor for C3b a C4b CR2 (CD21) receptor of B lymphocytes for CD3d a C3g CR3 (CD11b/CD18); CR4 (CD11c/CD18) receptors for ic3b opsonin IgG γ Fc receptor bacteria macrophage opsonin C3b CR1 receptor
MOLECULES OF NESPECIFIC RECOGNITION Recognition of foreign (microbial) structures Pathogen-associated molecular pattern PAMP (Microbe-associated molecular pattern MAMP) LPS of G- bacterias, lipoteichoic acid of G+ bacterias etc. Pattern-Recognition Receptors PRRs CD14, TLR etc. Aktivation of C3 convertase by the microbial surface m(activation of alternative pathway of complement ) Recognition of foreign or estranged cells changes (lack) of MHC I molecules tumor associated molecules downregulation of CD47 on the surface of old cells EXAMPLES OF PATTERN-RECOGNITION RECEPTORS Toll-like receptors recognized first as toll-receptors of Drosophila binding molecules with lipophilic part recognizing various microorganismes (see next slide) CD14 receptor on the surface of monocytes and neutrophils bindiung LPS of Gram negative bacterias various other biological function (induction of proinflamantory cytokines) NOD molekuly intracellular molecules recognizing engulfed micoorgnismes (in cytoplasma) Manose binding receptor lectin binding manose and fucose, facilitate phagocytosis SR - scavenger receptor recognizing LPS and lipoteichoic acid TOLL-LIKE RECEPTORS TLR TLR 1, TLR 2 TLR 3 recognized structure lipopeptids (Gram negative bacteria), lipoteichoic acid (Gram positive bacteria) lipoarabinomanane (mykobacteria) zymosan (fungi) double-stranded RNA (viruses) TLR 4 (+ CD14) lipopolysacharide (Gram negative bacteria) TLR 5 TLR 6, TLR 2 TLR 7, TLR 8 TLR 9 flageline (bacteria) bacterial lipids single-stranded RNA (viry) unmethylated CpG (bacteria) PHAGOCYTOSIS The oldest immune reaction, exist already at primitive organisms The reaction providing ingestion and processing of foreign, pathological or dead cells and corpuscular materials Tizard chapter 3, pp. 24-34
ENDOCYTOSIS TERMINOLOGYAND STAGES CHEMOTACTIC SIGNALS bacteria (formylpeptides) PHAGOCYTOSIS PINOCYTOSIS STAGES chemotaxis recognition of particles (opsonization) ingestion digestion release of of products of degradation OR presentation of antigen infected epithelium injured epithelium IL-8 PAF C3a a C5a leukotriene B 4 NEUTROPHIL makrophage PHASE OF NEUTROPHIL TRANSMIGRATION FROM VESSEL ROLLING MOVEMENT Expression of selectins ATTACHMENT DIAPEDESIS Expression of integrins and adhesins of immunoglobulin family RECOGNITION IN PHAGOCYTOSIS Pattern-Recognition Receptors CD14 - receptor pro LPS TLR (2, 4) receptor for manose, for galactose scavenger receptor... Fc receptors (FcRγ) Komplement receptors OPSONIZATION
MECHANISM OF OPSONIZATION PROCESS OF PHAGOCYTOSIS bakterie binding of particles on surface opsonin IgG γ Fc receptor makrofág opsonin C3b složka komplementu CR1 receptor ingestion -phagosome fusion of phagosome with lysosome digestion in phagolysosome releasing of products of degradation REACTIVE SUBSTANCES OTHER MOLECULES SUBSTANCES IN LYSOSOMES lysozyme destroys bacterial wall defensins kill gram-positive bacteria hydrolases destroy bacterial structure lactoferin binds iron collagenses destroy connective tissues REACTIVE RADICALS OF OXYGEN (AND CHLORINE) ROI O2 -, OH -, 1O 2-, H 2 O 2, HOCl, NH 2 Cl respiratory burst REACTIVE RADICALS OF NITROGEN NOI NO, NO 2, HNO 2 Defensins mainly intracellular location described 50 α-defensins, 20 β-defensins kill bacteria, enveloped viruses and fungi Lysozyme found in all body fluids including neutrophil granules destroys bacterial peptidoglycans (G+ bacteria) Fibronectin found in blood and extracellular matrix important in coagulation accelerates phagocytosis
REACTIVE RADICALS OF OXYGEN NATURAL CYTOTOXICITY Reaction of innate immunity against intracellular pathogens, tumor cells or foreign cells in allotransplantation Tizard 366-369 TWO TYPES OF CELL DEATH CYTOTOXIC MECHANISMS NECROSIS induction of inflammation NK Mf non secretory pathway TNF Fas ligand APOPTOSIS APOPTOSIS phagocytosis without inflammation Tc RECOGNITION of target cell ACTIVATION of cytotoxic cells secretory pathway LYSIS APOPTOSIS perforins granzyme B Tizard 202-203
DIFFERENCES BETWEEN NATURAL AND ADAPTIVE CYTOTOXICITY nonspecific Effector cells NK Tc specific recognition MHC I Ag presentation cytotoxic constantly present appear after activation substances cytotoxic reaction the same in both types NK - cells natural killer large granular lymphocyte permanently present azurophil granules containing perforins and granzymes non-adhere and non-phagocyting main cell in natural cytotoxicity: against viruses against tumores RECOGNITION BY NK CELLS MECHANISMS OF CYTOTOXIC REACTION MHC I KIR Fas ligand Fas inactive ICE virus growth factor demage of DNA healthy cell GP NKAR NK ICE granzymes pro IL-1β IL-1β substrate Tc NK perforins pores DNase APOPTOSIS Target cell injured cell NK
MECHANISMS OF CYTOTOXIC REACTION granule Cytotoxic cell perforines INTERFERONS Target cell INTERFERONS MECHANISM of INTERFERONS ACTION Type I IFNα, IFNβ produced by the virus-infected cells inactivation of viruses OR binding to the surfaces of cells (CDw118, CDw119) = inhibition of cell infection Type II IFNγ produced by Th1 lymphocytes marked regulatory function activation of macrofages (and other cells) inaktivní proteinkináza aktivní PK P1 INTERFERON VIROVÁ ds RNA INHIBICE VIRŮ aktivní RNAáza L inaktivní 2 5 oligo - adenylátsyntetóza aktivní 2 5 OAS elf2 fosforylovaná elf2 inaktivní RNAáza L