Lecture 11 - Effector responses against infectious agents (1) Flashcards
What type of receptors activate many of the cells of the innate immune system?
Pathogen Recognition Receptors (PRRs)
What are the 6 main cells if the myeloid lineage that make up the innate cell responses? [6]
- Mast cells
- Macrophages
- Dendritic cells
- Neutrophils
- Basophils
- Eosinophils
List 3 phagocytes of the innate immune system. [3]
- Macrophages
- Dendritic cells
- Neutrophils
List 3 granulocytes of the innate immune system. [3]
- Neutrophils
- Basophils
- Eosinophils
Where are Macrophages found?
Only in tissues
Where are macrophages produced?
- From monocytes
- From embryonic cells
What are Neutrophils adapted for?
Good detection of pathogens
How do phagocytes kill a pathogen?
- Acidification of the phagosome
- The contents within the phagolysososme
How do granulocytes deal with pathogens?
Release toxic granules and chemical mediators
How are granulocytes activated?
By complement, antibody, and cytokines
Where are Mast cells found?
Only in tissues
Which antibody type is on mast cells?
IgE
How do Mast cells regulate the release of the granules?
At least two antibodies need to be activated
What is the role for Natural Killer cells?
Using cytotoxic molecules to kill ‘altered’ cells
How do natural killer cells know which cell to kill?
An inhibitory receptor binds to MHC class I to inhibit the activation of NK cells
What happens to a cell that comes into contaact with an NK cell but does not express MHC class I?
They are killed
What is the role of the complement system?
- Component of the innate immune system
- Provides early antibody-independent killing of pathogens
How are the complement protein activated?
They are cleaved into two fragments
- First fragment does little
- Second fragment has binding site and enzymatic site
What are the three pathways of complement activation? [3]
- Classical pathway
- Alternative pathway
- Lectin pathway
What happens during the classical pathway?
Complement binds to an antibody bound to the pathogen surface
What happens during the alternative pathway?
Complement binds to pathogen surfaces
What happens during the Lectin pathway?
Complement binds to Mannose binding proteins bound to the pathogen surface
What is the general sequence of the classical pathway?
- C1q binds to IgM
- C1s activates
- Causes cascade of reactions
- C3 is cleaved to C3b at the end
True or False? The alternatice pathway of the complement system requires antibodies.
False. It does not require antibodies
