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| Innate immunity |
Immunity refers to the resistance of a host to the pathogen and their toxic products.
There are two types of immunities:
1. Innate (in birth)
2. Acquired (gained)
Innate immunity : it is the immunity due to genetic or constitutional make up of an individual. It may be specific against a particular pathogen or non-specific.
Factors :
1. Age : it is disregulated with age and is characterized by persistent inflammatory response.
2. Hormones: steroid hormones modulate the development and activity of both innate and adaptive immunity.
3. Nutrition : dietary components and micronutrients have profound effect on innate immunity.
Mechanism
Innate immunity responses are not specific to a particular pathogen in the way that the adaptive responses are.
These depend on a group of proteins and phagocytic cells that recognise conserved features of the pathogen and become quickly activated to destroy them (invaders).
Skin and other epithelial surfaces including lung and gut , provide physical barrier.
Tight junctions between neighbouring cells prevents easy entry of pathogens.
Specialized epithelial lining in respiratory and gastrointestinal tract minimize infection.
Tear mechanically wash away the particals and hydrolytic enzymes, lysozymes destroy bacteria in eye.
