Cells of the innate immune system Flashcards
(40 cards)
What are the characteristics of the innate immune response?
Broadly specific
Doesn’t show immunological memory
Immediate
The immune system comes into play in most cases
TRUE or FALSE
FALSE
Most cases the immune system does not come into play since immunological barriers are very effective
Which cell gives rise to the innate immune cells?
Myeloid progenitor
What developmental pathway gives rise to the adaptive immune cells?
Myeloid developmental pathway
Where are Neutrophils found?
IN the blood and tissues
Where are Monocytes found?
In the blood
Where are Macrophages found?
IN the tissues
Where are Dendritic cells found?
In the tissues
Where are eosinophils found?
In the blood and tissues
Where are mast cells found?
In the mucosa and connective tissue
Where are basophils found?
In the blood
Where are natural killer cells found?
In the blood and tissues
Which cells are phagocytic?
Macrophages, monocytes, Dendritic cells and Neutrophils
Which cell is phagocytic and promotes inflammation?
Eosinophil
Which cells promote inflammation?
Mast cells and Basophils
Which cell kills virus infected cells?
Natural killer cells
Which types of cells does the myeloid progenitor give rise to?
Megakaryocytes Erythrocytes Dendritic cells Monocytes Leukocytes
What is a distinguishing feature of Natural Killer cells?
Form part of the innate immune system
But originate from the lymphoid progenitor cell
What are the 3 sentinel cells?
Neutrophils - in blood, migrate to tissue in response to infection = short lived
Monocytes - leave blood to form macrophages, live longer
Dendritic cells - many different cell types
Describe the process of phagocytosis
Chemotactic gradient attracts phagocyte to the zone of infection
Phagocytic cell comes into contact with pathogen
CSM recognition structure recognises structures of the infectious agent
PAMPs on pathogens bind to PRRs on phagocytic cells - adherence
Phagocytic cells activate via signals sent from the PRRs
Phagocytic cells release pseudopodia and engulf the pathogen
Pseudopodia fuse to form a vacuole and trap the pathogen - phagosome
Lysosomes move towards and fuse with phagocome to release lysozyme
This forms a phagolysosome
Lysosomes contain substances that destroy the trapped microbe
Release of degradation products
What are the ways in which the phagolysosome kills a pathogen
Oxidative killing - reactive oxygen species
Nitric oxide-related killing - reactive oxygen intermediates
Non-oxidative killing mechanisms - lysozyme breaks down the bacterial cell wall
What is the inflammatory response?
Process by which the phagocytic cell enters the zone of infection
Blood is the transport system - inflammatory mediators are released here to let cells know about the infection, so they can move from the blood into the tissues
What are the two inflammatory mediators used in the inflammatory response?
Inflammatory chemicals - histamines released by mast cells and basophils
Lipopolysaccharides - released by gram negative bacteria
Describe the process of the inflammatory response
Molecules are expressed which are not normally expressed
This leads to upregulation of P-selectin on vascular endothelium
Neutrophils recognise P-selectin by PSGL-1
Neutrophils adhere to the vascular endothelium and stops transit through blood
Neutrophils and vascular endothelium express adhsion molecules
Adhesion molecules released by the endothelium recognise those released by neutrophils = stronger adhesion
Neutrophils squeezes in between endothelial cells -> diapedesis
