1. BASIC CONCEPTS OF INNATE IMMUNITY, INFLAMMATION
2ND SEMINAR
BASIC CONCEPTS OF INNATE IMMUNITY,
INFLAMMATION

2. Physical, chemical, microbiological barriers
CONTACT SURFACES
Physical, chemical, microbiological barriers
EYE
SKIN
WALDEYER RING
Tonsils, adenoids
Palatinal, pharyngeal
lingual and tubar tonsils
Sinuses
Trachea
Lungs
AIRWAY SYSTEM
Oral cavity
Esophagus Stomach
Alimentary tract
GASTROINTESTINAL SYSTEM
Kidney
BladderVagina
UROGENITAL SYSTEM
Change figure
DAMAGE TO ANY OF THESE BARRIERS MAY LEAD TO INFECTION

3. FIRST LINE OF DEFENSE

4. PHYSICAL, CHEMICAL AND MICROBIOLOGICAL BARRIERS
GI tract
Stomach: pH of 3-4; small intestine: pH of 6-8
Digestive enzymes
Mucus
Antibacterial peptides e.g. defensins, cryptidins
Peristalsis, diarrhoea, vomiting
Normal flora H. pylori – making basic pH
Skin
Tight junctions
Keratin layer
Antibacterial peptides e.g. defensins
pH of 5.5
Fatty acids
Normal flora
Burns  susceptibility to infections
Eye
Tear film (oils, lactoferrin, mucin and lysozyme)
Urogenital tract
Flushing out
Vagina: pH of , normal flora (Lactobacillus  lactic acid)
Respiratory tract
Ciliary movement – constant outward flow
Coughing, sneezing CF - impaired cilia movement
Defensins: highly positively charged, forming pores in bacterial membranes. Have an anti-viral activity as well.

5. MICROBIOLOGICAL BARRIERS
The normal flora
SKIN, NASO-ORO-PHARYNGS, GUT, VAGINA
Symbiotic, non-pathogenic microbes, living in „peaceful” commensalisms
Beneficial features:
Digesting non absorbable food compounds e.g. cellulose
Producing vitamines, antimicrobial molecules, regulating pH
Compete with pathogenic microbes – survival of the fittest
Providing constant low-dose antigen exposure
Helping the development of the immune system
Maintainig tolerance
BALANCE!
(antibiotics – probiotics)
Some facts about the normal flora:
There are 100-times more bacterial genes than eukaryotic genes
Cells of human body: 90% microbes, 10% human
Gut bacteria: more than 500 microbial species (approx. 1.5 kgs)
Human cell population: 1013

6. Gut normal flora play an important role in:
Development of mucosal and systemic immunity
Normal development of peripheral lymphoid organs
- Maintenance of basic level of immunity

7. ORGANIZATION OF IMMUNE CELLS UNDER EPITHELIAL SURFACES
Epithelial cells
Stroma cells
Dendritic cell
Granulocyte
Macrophage
NK cell
NKT cell DC
PERIFÉRIÁS SZÖVETEK
TISSUE–SPECIFIC CELLULAR COMMUNICATION NETWORKS

8. BY THE INNATE IMMUNE SYSTEM
RECOGNITION
BY THE INNATE IMMUNE SYSTEM

9. Cell-Cell collaboration
DEFENSE SYSTEMS
ADAPTIVE IMMUNITY
INNATE IMMUNITY
SENSING
RECOGNITION
SIGNALING
RESPONSE
SENSING
RECOGNITION
SIGNALING
RESPONSE
Cells
Receptors
Signaling pathways
Cell-Cell collaboration
Effector functions

10. RECOGNITION RECEPTORS OF INNATE IMMUNITY
Pattern Recognition Receptors (PRRs)
recognise molecular patterns as danger signals
can be classified as PRR families:
Lectins
Toll-Like Receptors (TLRs)
Nod-Like Receptors (NLRs)
RIG-Like Receptors (RLRs)
Scavenger receptors
molecular pattern: characteristic molecules that are expressed in high amounts by cells or microbes
Patogen-Associated Molecular Patterns (PAMPs): molecules that are expressed unlike human cells, usually essential for the survival or replication of pathogens
Damage-Assoiated Molecular Patterns (DAMPs): molecules released after cellular damage

11. TOLL-LIKE RECEPTOR FAMILY

12. DANGER SIGNALS ARE TRANSLATED TO CYTOKINE SECRETION THROUGH VARIOUS MOLECULAR SENSORS IN DC SUBTYPES4 6 6 2 1 1 5 10 3 7 9 7 8
NLR
RLR
RLR
Plasmacytoid DC
Conventional DC
IFNα IFNβ
IL-1β
IL-12/23
IL-10
TLR1 – bacterial lipoprotein (together with TLR2)
TLR2 – bacterial lipoprotein, peptidoglycane, lipoteicholic acid
(heteromer with TLR1 and TLR6)
TLR3 – viral dsRNA
TLR4 – bacterial LPS
TLR5 – bacterial flagellin
TLR6 – bacterial lipoprotein (together with TLR2)
TLR7 – viral ssRNA
TLR8 – viral ssRNA
TLR9 – unmethylated CpG DNA
TLR10 – modified viral nucleotides
NLRs – microbial products, DAMPs
RLRs – viral ssRNA

13. EFFECTOR MECHANISMS OF INNATE IMMUNITY
COMPLEMENT SYSTEM
KILLER CELLS
PHAGOCYTIC CELLS

14. NEUTROPHIL - MACROPHAGE - DENDRITIC CELL
PHAGOCYTIC SYSTEM
NEUTROPHIL - MACROPHAGE - DENDRITIC CELL
Gatekeeper function
Sensing commensals and pathogens
Rapid activation of innate immunity
Priming adaptive immune responses
Maintenance of self-tolerance
Defense against infectious diseases
Elimination of tumor cells
Transplantation rejection

15. RECEPTORS ON MACROPHAGES
TLR4 + CD14
Scavanger receptor
Mannose receptor
MHCI
TLRs – PAMPs
FcRI (CD64)
Ag + Ab complex
FcRII (CD32)
MHCII
FcRIII (CD16)
LFA1 (CD11a/CD18)
CR1 (CD35)
Cell adhesion molecules
CR3 (CD11b/CD18)
Complement receptors

16. GLYCOSYLATION OF PROTEINS IS DIFFERENT IN VARIOUS SPECIES
Eukaryotic cells
Prokaryotic cells
Mannose
Galactose
Glucoseamin
Mannose
Sialic acid

17. MANNOSE RECEPTORS ON PHAGOCYTES
Bacterium
Mannose
Mannose Receptor
Macrophage/dendritic cells

18. COLLECTION OF ENVIRONMENTAL INFORMATON
PHAGOCYTOSIS, RECOGNITION RECEPTORS, SIGNAL TRANSDUCTION, EFFECTOR MECHANISM
Pattern recognition
Receptors (PRR)
UPTAKE
Macropinocytosis
Receptor-mediated endocytosis
Phagocytosis
COLLECTION OF ENVIRONMENTAL INFORMATON
Lectins: receptors ( or plasma proteins) that bind to carbohydrates. On macrophages one finds mannose rec. And glucan receptors.
Scavenger receptor binds various substrates generally negatively charges (sulfated polysaccharides, nucleic acids, lipoteic acid bound in the cell wall of Gram positive bacteria)
Engagement of PRR triggers phagocytosis and cytokine production

19. PHAGOCYTOSIS

21. INNATE IMMUNITY Pathogen recognition
 PRRs (TLRs, lectins, NLRs, RLRs, scavenger receptors)
Cell activation
 Increased phagocytic activity, intracellular killing (reactive oxygen species (ROS), lysosomal enzymes), chemokine and cytokine secretion
Antigen processing
 Phagocytosis/endocytosis  degradation in phagolysosomes
Antigen presentation (later)

22. ACUTE INFLAMMATION
&
ACUTE-PHASE RESPONSE

23. ACUTE INFLAMMATION
A rapid response to an injurious agent that serves to deliver leukocytes and plasma proteins to the site of injury

24. TRIGGERS OF ACUTE INFLAMMATION:
Infections
Trauma
Physical and Chemical agents (thermal injury, irradiation, chemicals)
Tissue Necrosis
Foreign bodies (splinters, dirt, sutures)
Hypersensitivity or autoimmune reactions
MAJOR COMPONENTS OF INFLAMMATION:
Vascular response:
Increased vascular diameter  Increased flood flow.
Endothelial cell activation
increased permeability that permits plasma proteins and leukocytes to leave the circulation and enter the tissue  edema
increased expression of cell adhesion molecules e.g. E-selectin, ICAM
Cellular response:
Migration of leukocytes (diapedesis/extravasation), accumulation, effector functions

25. THE CLASSIC SYMPTOMS OF INFLAMMATION: Redness (rubor) Swelling (tumor)
Heat (calor)
Pain (dolor)
Loss of function (functio laesa)
You ought to know which classic symptom is caused by which pathophysiological process

26. Resident phagocytes get activated by PRR signalization upon recognition of danger signals 
Production of cytokines and chemokines,
Intracellular killing,
Antigen presentation (activation of adaptive responses)

27. ORDER OF INNATE CELLS APPEARANCE IN THE INFLAMED SITE

28. NEUTROPHIL GRANULOCYTES
68% of circulating leukocytes, 99% of circulating granulocytes
Phagocytic cells
Are not present in healthy tissues
Migration  elimination of pathogens (enzymes, reactive oxygen intermediates)
Main participants in acute inflammatory processes
LFA-1: Lymphocyte-function associated antigen-1
Sialylated Lewis X Ag

29. NEUTROPHIL CHEMOTAXIS
acPGP: N-acetyl Proline-Glycine-Proline – neutrophil chemoattractant
MMP: matrix metalloproteinase

30. MIGRATION OF NEUTROPHILS

31. Neutrophil Transendothelial Migration (Diapedesis)

32. Pathogens activate macrophages to release cytokines and are then phagocytized and digested in phagolysosomes

34. CHEMICAL MEDIATORS
Local effect & systemic effect

35. CHEMICAL MEDIATORS Vasodilation Prostaglandins (PG), nitric oxide (NO)
Increased vascular permeability
vasoactive amines (histamine, serotonin), C3a and C5a (complement system), bradykinin, leukotrienes (LT), PAF
Chemotactic leukocyte activation
C3a, C5a, LTB4, chemokines (e.g. IL-8)
Fever
IL-1, IL-6, TNFα, PGE2
Pain
Prostaglandins, bradykinin
Tissue damage
Neutrophil and Macrophage products
lysosomal enzymes
Reactive oxygen species (ROS) NO
NSAIDs and Paracetamol:
inhibiting COX-1 and COX-2  preventing the synthesis of prostaglandins

36. ACUTE-PHASE RESPONSE PROTEINS
Pentraxin family:
CRP – opsonization, complement activation
SAP – opsonization, complement activation, binding of mannose/galactose
Collectin family:
SP-A/D – collectins of lungs
MBL – part of complement system
Complement proteins (C1-C9)
Fibrinogen – blood clotting
During an APR their concentration increases up to x1000
SP-A/D: Surfactant Protein A and D

37. RESOLUTION OF ACUTE INFLAMMATION