Innate Myeloid and Lymphoid Cells Flashcards
What are the two types of macrophages?
There are two types of these - tissue resident macrophages and recruitment macrophages
What do tissue resident macrophages do?
- They capture and destroy pathgoenic intruders and are found in every tissue of the body.
- They also recruit other innate effector cells through chemokines and are essential for wound healing and tissue remodelling.
- They are also needed for development e.g. making fingers.
- They also maintain tissue homeostatis by removing apoptitic cells and maintain tissue resident T cells.
What growth factor do macrophages rely on?
Colony stimulating factor 1 or Il-34 or GM-CSF
In health what do macrophages do?
They mainly remove apoptosed cells
What are recruited macrophages?
They are derived from classical blood monocytes and recruited in response to inflammation. They are short lived
What do recruited macrophages do?
They are highly phagocytic and bactericidal and produce pro-inflammatory cytokines and chemokines
They also present T cells with any antigens on MHC class 2
What is dysregulation of macrophages a feature of?
Severe covid19 - this is because recruitment of monocytes with an aggressive inflammatory phenotype are disregulated in the lungs
What do macrophages do when activated?
They are activated by DAMPS and can become different macrophages and respond to specific infections. Monocytes come into the cell via chemokine receptors which are highly pro-inflammatory.
What are neutrophils?
They are polymorphonuclear phagocytes that are short lived in the blood.
What do neutrophils rely on for development?
GM-CSF and G-CSF
How are neutrophils recruited to the infection site early?
With chemokines CXCL1, CXCL2, IL-8 or fMLP, leutrienes
Do neutrophils die at the site of infection?
Yes and are cleared up by tissue resident macrophages
How do neutrophils kill?
Phagocytosis
Degranulation (these can be released to kill - are toxic)
NETS
How do neutrophils kill via phagocytosis?
Pathogens are coated in antibodies and complement and neutrophils take up these particles into vesicles where they are broken down by things such as toxic nitrogen products, toxic-oxygen derived products, anti-microbial peptides, emzymes or via competition e.g. starving the pathogens of iron
What are the different kinds of granules that neutrophils can release?
Primary
Secondary
Tertiary
Antimicrobial but can help them navigate through tissue
What do NETS do?
Release of histone proteins and anti-microbial peptides to catch the microbes and destroy them
What is chronic granulomatous disease?
A disease which occurs when you have issues with neutrophils because of defects in NADPH.
You become infected with opportunistic pathogens which causes accummulation of chronically infected phagosytes and formation of granulomas.
What are eosinophils?
These circulate in low numbers in the blood and are short lived. You can find them via staining with acidophilic dyes.
What is needed for eosinophil development?
IL-5 and IL-3 and CSF2
How are eosinophils recruited?
Recruited via the CCR3 in response to chemokines CCL11, CCL24, CCL26
What type of receptors do eosinophils have?
Cytokine, lipid mediators, Fc, PRRs