Immunology Flashcards
What are the 3 parts of the traditional innate immune system?
1) Barrier and chemical mechanisms - complement system
2) PRR - pattern recognition receptors
3) Cellular component
What are the 5 major components of the innate immune system?
1) Pattern recognition receptors
2) Antimicrobial peptides
3) Cells
4) Complement components
5) Cytokines
What are the 2 parts to the adaptive immune system?
1) Humoral - Ab
2) Cellular - B and T lymphocytes
What are the 5 PRRs?
1) Toll-like receptors
2) NOD-like receptors
3) Rigl-like receptors
4) C-type lectins
5) Scavenger receptors
What are the 8 types of cell of the innate immune system?
1) Macrohpages
2) Dendritic cells
3) NK cells
4) Neutrophils
5) Eosinophils
6) Mast cells
7) Basophils
8) Epithelial cells
What is meant by pattern recognition receptors?
Its an inclusive term for antigen recognition receptors in the innate immune system
What are 2 things that PRRs commonly recognise?
Pathogen associated molecular patterns (PAMPs)
Danger associated molecular patterns (DAMPs)
Is there diversity of type in PRRs?
Yes, but each immune cell carries identical receptor of a given type
What are the 2 broad groups of PRRs?
1) Cell surface (transmembrane) and intracellular receptors - TLRs, NLRs, RLRs, CLRs
2) Fluid-phase soluble molecules
Which 2 PRRs recognise LPS?
TLR4
CD14
Which 2 PRRs recognise Triacylated lipopeptides?
1) TLR 1
2) TLR 2
Which 2 PRRs recognise diacylated lipopetides?
1) TLR 2
2) TLR 6
Which PRR recognises flagellin?
TLR 5
Which cytokine is the first produced in response to infection?
IL1
Which intracellular PRR recognises single stranded DNA released by viruses when they begin to multiply in a cell?
TLR 9
What is the name of the fluid phase recognition molecules?
Collectins
Give 2 examples of collectins (fluid phase recognition molecules)?
1) Mannan-binding lectin
2) Surfactant protein A&D
What do collectins recognise?
Microbial complex carbohydrates
How do collectins bind to their substrate?
Bind via carbohydrate recognition domains (CRDs)
What 2 roles do collectins have once they’ve bound to their substrate?
1) Neutralisation of a pathogen
2) Recruitment of adaptive response
What do PRRs do once they have bound to their substrate?
Starts a cascade and cytokines are released to signal to the adaptive immune and innate immune system
IL1 is a cytokine released from what cells (3) and what are its 3 targets and thus effects?
Released from
macrophages, endothelia and epithelia
Effects
Endothelia - increased coagulation and inflammation
Hepatocytes - leads to increased acute phase proteins
Hypothalamus - increased fever
TNF is released from what cells 2, has what targets and thus what effects 4?
Released from
Macrophages and T lymphocytes
Targets and effects
Endothelia - increased coagulation and inflammation
Hepatocytes - increased acute phase proteins
Neutrophils - increased activation
Hypothalamus- increased fever
IL6 is released from what cells 3, has what targets and what effects 2?
Released from
Macrophages and T lymphocytes and endothelia
Targets and effects
Hepatocytes - increased acute phase proteins
B lymphocytes - increased proliferation
IL23 is released from what cells 2, has what targets and thus what effects 1?
Released from
macrophages, dendritic cells
Targets and effects
T lymphocytes - increased production IL17
What is the major role of macrophages in innate immunity? 4
1) Phagocytose and kill bacteria
2) Produce antimicrobial peptides
3) Bind LPS
4) Produce inflammatory cytokines
What is the major role of plasmacytoid dendritic cells in innate immunity? 1
1) Produce large amounts of interferon which has antitumour and antiviral activity
What is the major role of myeloid dendritic cells in innate immunity? 1
1) Strong producers of IL 12 and IL 10
Where are plasmacytoid dendritic cells found in the body? 2
T cell zones of lymphoid organs
Circulate in the blood
Where are myeloid dendritic cells found in the body? 4
T cell zones of lymphoid organs
Interstices of lung heart and kidney
Skin epithelia and thymic medulla
Circulate in blood
What is the major role of natural killer cells in innate immunity?
Kill foreign and host cells that have low levels of MHC+self peptides
They express NK receptors that inhibit NK function in the presence of high expression of self-MHC
What is the major role of neutrophils in innate immunity?
Phagocytose and kill bacteria and produce antimicrobial peptides
What is the major role of eosinophil’s in innate immunity?
Kill invading parasites
What is the major role of mast cells and basophils in innate immunity?
Release TNF, IL 6 and IFN in response to a variety of PAMPs
What is the major role of epithelial cells in innate immunity?
Produce antimicrobial peptides
Tissue specific epithelia produce mediator of local innate immunity eg. lung epithelia cells produce surfactant proteins that bind and promote the clearance of lung invading pathogens
What are the 2 primary lymphoid organs and what takes place there?
1) Bone marrow
2) Thymus
Lymphocyte development and selection - bone marrow for B cells and thymus for T cells
What are the 3 secondary lymphoid organs and what takes place there?
Immune response takes place there
1) Spleen (white pulp)
2) Lymph nodes
3) Mucosal surfaces
There arent enough genes to code for every kind of B or T cell receptor, how is such great variability achieved?
VDJ recombination