MICR104A Innate Immunity

Innate Immunity

If infectious agents such as bacteria and viruses invade the body, it must be rapidly recognized and destroyed

acute inflammation

the most important innate mechanism

Inflammation

the response of tissues to invading microorganisms or tissue damage

neutrophils and macrophages

Inflammation involves the activation and directed migration of many different cells such as these

Recognition

the first step in innate immunity involves the recognition of microorganisms and molecules released by damaged cells.

sentinel cells

damaged cells are detected by this which have surface receptors

PAMPs

recognizes the damaged cells that was detected by the surface receptors of sentinel cells

Pathogen-Associated Molecular Patterns

PAMPs stands for

since some microbes are highly diverse and can mutate and change their molecular structures

the sentinel cell receptors are not designed to recognize all possible microbial molecules

Damage-Associated Molecular Patterns

DAMPs stands for

Pattern Recognition Receptors

PRRs stands for

PRRs

receptors present in sentinel cells

peptidoglycans, lipoteichoic acids

Examples of molecules in microorganisms recognized by surface receptors of sentinel cells (PAMPs) IN GRAM-POSITIVE BACTERIA

LPS

Examples of molecules in microorganisms recognized by surface receptors of sentinel cells (PAMPs) IN GRAM-NEGATIVE BACTERIA

Glycolipids

Examples of molecules in microorganisms recognized by surface receptors of sentinel cells (PAMPs) IN ACID-FAST BACTERIA

Mannans

Examples of molecules in microorganisms recognized by surface receptors of sentinel cells (PAMPs) IN YEASTS

Toll-like receptors

TLRs stands for

TLRs

Receptors expressed on macrophages and mast cells, as well as dendritic cells, eosinophils and epithelial cells in respiratory tract and intestine

Cytokines

genes of proteins activated which are optimized to combat the bacteria or viruses by triggering innate immune defenses

10 (12 if intracellular are included)

How many TLRs are there

heparan sulfate

TLRs recognizes molecules produced by damaged tissues such as fragments of this binds to TLR4 and heat shock proteins

TLR4

recognizes lipopolysaccharides

TLR2

recognizes peptidoglycans, lipoproteins, glycolipid

lipoarabinomannan

TLR2 recognizes this in glycolipid

Mycobacterium tuberculosis

lipoarabinomannan is from

TLR5

recognizes flagellin

TLR9

intracellular sensor of bacterial DNA

TLR3 and TLR7

recognizes viral double-stranded RNA

TLR7 and TLR8

recognizes viral single-stranded RNA

CD14

PAMP receptors that binds to bacterial LPS

Mannan & glucan receptors

PAMP receptors that binds to microbial carbohydrates

CD36

PAMP receptors that binds to bacterial lipoproteins

CD1

PAMP receptors that binds to microbial glycolipids

LPS-binding protein

Bacterial LPS cannot bind directly to TLR4 so they must bind first to this molecule

MD2 and CD14

Bacterial LPS cannot bind directly to TLR4 so they must bind first to these molecules ASIDE FROM LPS-binding protein