Innate, or nonspecific, immunity is the defense system with which you were born. It protects you against all antigens. Innate immunity involves barriers that keep harmful materials from entering your body. These barriers form the first line of defense in the immune response.
2. Cytokines of innate immunity
Definition
low molecular weight soluble proteins produced in
response to microbes and other antigens.
Pro-inflammatory cytokines have role in inflammatory
response
Types
1- IL-1, IL-6, IL-8 and TNF-α from macrophages → increase
vascular permeability and extravasation of neutrophils
and induce coagulation
2- IL-12 from macrophage → activates NK cells.
3- IFN- from NK cells → activates macrophages.
4- IFN-α from viral infected cells → inhibits viral replication
and prevents spread of virus to uninfected cells.
5. Process of Phagocytosis
Phagocytes engulf and kill microorganisms
Steps of phagocytosis:
• Chemotaxis
• Recognition and attachment
• Engulfment and creation of phagosome
• Destruction and digestion
6. • Chemotaxis, migration and attachment:
Infectious microbe enters sub-epithelial tissues,
macrophages are attracted to site of inflammation by
chemokines
• Ingestion:
Phagocytes engulf microbe by extending pseudopods
around it. Organism is included into vacuole called
phagosome. Lysosomal granules then fuse with phagosome
forming phagolysosome followed by digestion of organism
• Intracellular killing:
Activated macrophages produce antimicrobial and cytotoxic
substances destroying organism
A- oxygen- dependent
B- oxygen- independent
