1. Basic Immunology Mr.AYMAN.S.YOUSIF
University of Tabuk
Faculty of Applied Medical Science
Department of Medical Laboratory Technology
Basic Immunology
Mr.AYMAN.S.YOUSIF
MSc.Medical Microbiology & Immunology
Academic Year: ( )

2. Arms of Immune System Innate Immunity Mr.AYMAN.S.YOUSIF 11-12/02/2013
Lecture 2

3. Objectives At the end of this lecture, you should be able to:
Recognize the significance of the immune system in combating infection and disease.
know the humoral and cellular components of innate immunity.
Understanding the mechanism of action of the humoral and cellular components of innate immunity.
Understanding the major Function of innate immunity .

4. Arms of the Immune System

5. Innate (Non specific) Immune System
Also called natural or native immunity.
It is present at birth; provides the early (first) lines of defense against microbes.
Consists of barriers (defense mechanisms) that are in place even before infection and poised (ready) to respond rapidly to infections. but do not adapt to a particular pathogen (non- specific).
They respond in essentially the same way to repeated infections. (no have memory ).

6. Antigen recognition by Innate Immunity components
Several components of innate arm recognize what is foreign by
Detecting Certain CHO or lipid on the surface microorganism that are different from those on human cells .
Component of the innate arm have receptor called Pattern-recognition receptor that recognize a molecular pattern on the surface of microbe that is not present on human cells.
This receptors are called Toll-Like Receptor (1-10) .

7. Remember
It is important to remember that infection with an organism does not necessarily mean diseases, due to the immune system in most cases will be able to eliminate the infection before disease occurs.
Disease occurs only when
The bolus (dose) of infection is high.
when the virulence of the invading organism is great .
when immunity is compromised.(Immunecomprmised).

8. Important Components of Innate Immunity
1. Factors that Limit Entry of Microorganisms Into The Body.
A. Anatomical Barriers To Infections.
Mechanical Factors (Barrier) .
Chemical Factors (Barrier) .
Biological Factors (Barrier) .
2. Factors that Limit growth of Microorganisms Into The Body.
B. Humoral Barriers To Infection (Humoral components)
C. Cellular Barriers To Infection (cellular components )

9. First-Line Defense

10. A. Anatomical Barriers to Infections.
Factor
Mode Of Action
Physical
Epithelial surfaces
Very impermeable to most Infectious agents.
Mechanical
Keratin layer of intact skin
Acts as mechanical barrier.
Respiratory cilia
1. Elevate mucus containing trapped organisms.
The flushing action of tears and saliva
Helps prevent infection of the eyes and mouth.
Chemical
Fatty acids in sweat
Inhibit the growth of bacteria.
Lysozyme in tears and other secretions
( saliva & nasal secretion)
Breakdown the cell wall of bacteria.
Destabilize bacterial membranes.
The low pH of sweat and gastric secretions and vagina.
Prevents growth of bacteria
Surface phagocytes (e.g.. alveolar macrophages)
Ingest and destroy microbes.
Defensins (cationic peptides)
Create pores in microbial membrane
Biological
The normal flora of the skin , throat, colon ,vagina ,and in the gastrointestinal tract
Prevent the colonization of pathogenic bacteria by
Secreting toxic substances.
Competing with pathogenic bacteria for nutrients.
Attachment to cell surfaces receptor .

11. B. Humoral barriers to infection
The Anatomical barriers are very effective in preventing colonization of tissues by microorganisms.
when there is damage to tissues, The anatomical barriers are breached and infection is occurs.
Once infectious agents have penetrated tissues, another innate defense mechanism comes into play, namely Acute Inflammation.
Humoral factors play an important role in inflammation, which is characterized by edema and the recruitment of phagocyte cells.
These humoral factors (Soluble factors) are found in serum or they are formed at the site of infection.

12. Inflammation

13. B. Humoral Barriers to Infection.
Humoral Factor
Mode Of Action
Complement system
(proteins)
Increased vascular permeability.
Recruitment of phagocytic cells.
Lysis and opsonization of bacteria.
Coagulation system
Increase vascular permeability .
Act as chemotactic agents for phagocytic cells.
Directly antimicrobial(platelets).
Lactoferrin & transferrin (proteins)
Limit bacterial growth. By binding iron, an essential nutrient for bacteria.
Interferons (proteins)
Limit virus replication in cells.
Lysozyme
Breaks down the cell wall of bacteria.
Interleukin-1 -11
Induces fever and the production of acute phase proteins,
Opsonin (some of which are antimicrobial because they can opsonize bacteria)
Fever
Elevated temperature retards bacterial growth.
Informatory response
Limits spread of microbes

14. 
 progenitors
 Innate immunity largely involves granulocytes and macrophages (although macrophages can influence adaptive immunity) 
other cells are regulatory or involved with both adaptive and innate immunity and/or are precursors of another cell type 
 Adaptive immunity is mediated primarily by B and T lymphocytes
   
 

15. C. Cellular barriers to infection
Characteristics of cell & Mode Of Action
Neutrophils
(PMN)
PMNs are the first cells to arrive at a site of inflammation.
They phagocytose invading organisms and kill them intracellularly.
cells die once antigen is removed.
Contribute to direct tissue damage that occurs during inflammation.
1. Macrophages (Tissue macrophages) 2. Dendritic cells .
3. Monocytes (newly recruited )
Phagocytosis and intracellular killing of microorganisms.
Are capable of extracellular killing of infected or altered self target cells.
Contribute to tissue repair and act as antigen presenting cells.
Induction of specific immune responses.
1. Natural killer cell (NK)
2. Lymphokine Activated killer (LAK) cells.
Nonspecifically kill virus infected and tumor cells.
Are not part of the inflammatory response.
Are important in nonspecific immunity to viral infections and tumor surveillance.
Eosinophils
Have proteins in granules that are effective in killing
certain parasites.

16. Leukocytes = White Blood Cells

17. Phagocytic Leukocytes

18. PMNs
Polymorphonuclear Neutrophilic Leukocytes, a.k.a., PMNs. They are shorter lived than macrophages but have greater killing power.

19. Non-Phagocytic Granulocytes
Eosinophils are involved in allergic responses, inflammation, and release of Histamine; Histamine is released by Basophils.

20. Function of Innate Immune System
The Innate arm of our host defenses perform tow major Function .
Killing Invading Microbe .
Activate Acquired (Adaptive) immune processes
e.g. Neutrophil only kill microbe .
Macrophage (MQ) & Dendritic cell(DC)
Kill microbe and present Ag to Components of Acquired immunity specially Helper T cells (CD4) Which activate Acquired immunity

21. Activate Acquired (Adaptive) immune processes

22. Thank You