2. Natural immunity Flashcards
What is natural immune response?
It is innate immune response which provides immediate defense
What is acquired immune response?
It is adaptive immune response which develops with time
What is the functional relationship of innate and adaptive immune response?
- Pathogen recognition and initial attack
- Transmission of Pathogen Information to Adaptive Immune System
- Specific Attack on Pathogens
What are the mechanical barriers for first line defense?
skin, mucous membranes, cough, sneeze
What are the chemical barriers for first line defense?
skin pH: ~5,5
stomach pH: 1,2-3
What are the biological barriers for first line defense?
in the mouth saliva contains antibacterial agents
- defensin (also in toothpaste)
- lysozyme (also in toothpaste)
- lactoperoxidase (also in toothpaste)
- lactoferrin (also in toothpaste)
- antibody – natural IgM ; IgA
What are the molecules for first line defense?
Complement system
IgA
What are the cells for first line defense?
Innate lymphoid cells
First line barrier:
-> What does the The SKIN / MUCOUS MEMBRANES contain?
Mucus contains antimicrobial secretions
First line barrier:
In general defensins are expressed along the first line barriers which are ___ (3)
- In salivary gland
- In Paneth cells of the small intestine
- In many leukocytes (e.g. neutrophils)
What are defensins? What do they form?
Most defensins are amphipathic molecules (positively charged and hydrophobic parts), and form holes in the membrane.
2 examples of defensins of the saliva
Alpha-defensins HNP 1- 4
Beta-defensins hBD1 hBD2 hBD3
What is the origin of Alpha-defensins HNP 1- 4?
- Neutrophils
- Gingival sulcus
- Sites of inflammation
- Salivary duct cells
What is the origin of Beta-defensins hBD1 hBD2 hBD3?
Epithelia, salivary ducts
What is lysozyme?
peptidoglycan N-acetylmuramoyl hydrolase that destroys bacterial cell wall by breaking glycosidil bonds between peptidoglycan components
What are 2 types of phagocytes?
- Neutrophils
- Macrophages
Which phagocytes are the most abundant leukocytes in the circulation appear first at site of infection?
Neutrophils
Macrophages mature from ___ in tissue
circulating momocytes
Characteristics of MPS (mononuclear phagocyte system)
Contain tissue-resident macrophages and recruited macrophages
Overview of phagocytosis and intracellular killing
I. Recognition and attachment - microbes bind to phagocyte receptors
II. Engulfment
- Phagocyte membrane zips up around microbe
- Fusion of phagosome with lysosome
III. Killing and degradation
- Killing of microbes by by ROS
- Degradation of microbes by lysosomal enzymes in phagolysosome
(ROS: highly reactive oxidizing agents
NO combines with superoxide to produce highly reactive peroxynitrite radicals(
What is the cause of CGD (Chronic granulomatous disease)?
Failure of phagocyte oxidase: Defective production of reactive oxygen species results in a failure to kill phagocytosed microbes.
What is granular formation?
Composed of activated macrophages, which try to eliminate the microbes
2 activation types of recruited macrophages
Elimination of apoptotic cells by macrophages
What are the 3 important granulocytes?
- Neutrophil
- Eosinophil
- Basophil
What is the function of neutrophil?
Phagocytosis
What is the function of eosinophil?
Degranulation against parasites
What is the function of basophil?
Degranulation against extracellular bacteria