24/04/2023
The Innate Immune System
Innate vs Adaptive Immunity
The innate immune system is the first line of defence, involving non-specific generalised
responses including complement and phagocytosis. The adaptive immune system adapts as
the pathogens adapt, i.e. the flu involves B and T cells and antibodies.
Cells involved in the innate immune response are macrophages, mast cells, dendritic cells,
complement proteins, NK cells, and the granulocytes (neutrophils, basophils and
eosinophils).
Cells involved in the adaptive immune response are B cells, T cells, antibodies and
cytokines (inflammatory mediators of the immune response).
The innate immune response is more rapid than the adaptive immune response.
Innate immune system
Effective from birth and present before exposure to pathogens.
Non-specific so cannot distinguish one agent from another.
Innate immune responses are the same on each encounter with the antigen.
Innate immune system consists of exterior and internal barriers.
Exterior barriers include skin and mucous membrane. Internal barriers include phagocytic
cells which ingest and destroy pathogens, and a complement system of soluble mediators
activated by bacteria.
Cells of the innate immune response include mast cells, macrophages, NK cells, dendritic
cells, monocytes, neutrophils, basophils and eosinophils. They recognise microbes through
pathogen-associated molecular patterns (PAMPs).
PAMPs
PAMPs are molecular on the microbial surface fundamental to the bacterial wall. They
include bacterial carbohydrates (e.g. lipopolysaccharide, and mannose), bacterial peptides
(e.g. flagellin, microtubule elongation factors), peptidoglycans, lipoteichoic acids, and nucleic
acids (e.g. bacterial/viral DNA/RNA).
Pattern recognition receptors (PRRs) are known as scavenger receptors, or damage-
associated molecular patterns (DAMPs).
PRRs are carbohydrate receptors (lectin).
PRRs are toll-like receptors (TLRs) on all phagocytic cells, some on dendritic cells, mast
cells, and B cells and can be upregulated in inflammation.
PRRs are NOD-like receptors (NLRs).
Opsonisation
Immune process which uses opsonins to tag a foreign pathogen for elimination by
phagocytes.
The Innate Immune System
Innate vs Adaptive Immunity
The innate immune system is the first line of defence, involving non-specific generalised
responses including complement and phagocytosis. The adaptive immune system adapts as
the pathogens adapt, i.e. the flu involves B and T cells and antibodies.
Cells involved in the innate immune response are macrophages, mast cells, dendritic cells,
complement proteins, NK cells, and the granulocytes (neutrophils, basophils and
eosinophils).
Cells involved in the adaptive immune response are B cells, T cells, antibodies and
cytokines (inflammatory mediators of the immune response).
The innate immune response is more rapid than the adaptive immune response.
Innate immune system
Effective from birth and present before exposure to pathogens.
Non-specific so cannot distinguish one agent from another.
Innate immune responses are the same on each encounter with the antigen.
Innate immune system consists of exterior and internal barriers.
Exterior barriers include skin and mucous membrane. Internal barriers include phagocytic
cells which ingest and destroy pathogens, and a complement system of soluble mediators
activated by bacteria.
Cells of the innate immune response include mast cells, macrophages, NK cells, dendritic
cells, monocytes, neutrophils, basophils and eosinophils. They recognise microbes through
pathogen-associated molecular patterns (PAMPs).
PAMPs
PAMPs are molecular on the microbial surface fundamental to the bacterial wall. They
include bacterial carbohydrates (e.g. lipopolysaccharide, and mannose), bacterial peptides
(e.g. flagellin, microtubule elongation factors), peptidoglycans, lipoteichoic acids, and nucleic
acids (e.g. bacterial/viral DNA/RNA).
Pattern recognition receptors (PRRs) are known as scavenger receptors, or damage-
associated molecular patterns (DAMPs).
PRRs are carbohydrate receptors (lectin).
PRRs are toll-like receptors (TLRs) on all phagocytic cells, some on dendritic cells, mast
cells, and B cells and can be upregulated in inflammation.
PRRs are NOD-like receptors (NLRs).
Opsonisation
Immune process which uses opsonins to tag a foreign pathogen for elimination by
phagocytes.
