innate immunity Flashcards
monocytes
circulating precursors to dendritic and macrophages
macrophages
tissue resident around the body, phagocytic and antigen presenting
dendritic cell
differentiate in the tissue, phagocytic and antigen presenting, travel to lymph nodes to activate t cells
neutrophils
circulating cells, highly phagocytic granulocytes
eosinophils
circulating cells, responed to IgE, can degranulate to remove parasites
basophil
circulating granulocytes in very low numbers
mast cell
tissue resident, source of cytokines, can degranulate
t lymphocytes
helper and cytotoxic, recircultae through lymph nodes, activated by dendritic cells
natural killer cells
innate immune cells which infected cells using granule contents
b lymphocytes
produce antibodies, activated by t cells, become antibody secreting plasma cells
innate immunity
barriers and deffences already in the tissue and the blood stream
adaptive immunity
t and b cells, focused at specific pathogen, antibodies or memory response
what happens if barriers are breached
- fragments of cells are released due to damage
- they bind to receptors
- induces inflammation through inflammatory cytokine release
4 cardial signs of inflammation
- redness
- heat
- swelling
- pain
pro inflammatory cytokines
- Interleukin - IL-1B, IL6
- Tumour necrosis factor - TNFa
effects of pro-inflammatory cytokines on the tissue
- pro-inflammatory cytokines are released into the tissue
- can act on the endothelial cells of blood vessels to weaken the tight junctions between cells = more permeable
- cause blood vessels to increase in diameter, increasing and slowing blood flow
- swelling in tissue can sensitise nerve endings in the skin, causing pain
what are DAMPs
danger-associated molecular pattern molecules
what are PAMPs
pathogen associated molecular patterns
- resident in barrier tissue with pattern recognition receptors on them
how to toll like receptors work
- change to transcription and cytokine released
1. recognition of pathogen transmits signal to the nucleus
2. protein NFkB assembles and bind the DNA instructing the cells to produce new proteins
3. include pro-inflammatory cytokines and cell surface molecules
how do phagocytic receptors work
- induce internalisation of pathogen
1. pathogen is recognised by receptors and phagocytosis is induced
2. pathogen is internalised in a phagosome, fuses with a lysosome containing antimicrobial peptides, lysozyme and nitric oxide
3. pathogen is broken down
what are the external receptors
- toll like receptors
- phagocytic receptors
what are the internal receptors
- cytoplasmic
- endosomal
what are complement proteins
collection of small proteins produced by the liver which circulate in the blood and are active once in the tissue
what are chemotaxis
controlled by chemokines, depending on tissue and point of infection different chemokines are produced