Linking Innate & Adaptive Immunity Flashcards
What are white blood cells?
A minor constituent of blood but they are the main cells involved in immunity
Where are dendritic cells present?
In major organs
What do dendritic cells do?
Phagocytose (gobble up) antigen and process it down to peptides
Where do dendritic cells migrate?
From organs (skin) to draining lymph node
What do dendritic cells present?
Peptides on MHC to other which blood cells (called T cells)
What can antibodies do?
Block the interaction between a molecule and its receptor
What can cytotoxic T cells do?
Come along and recognise an infected cell
What is APC?
Antigen presenting cell (includes any cell which can present antigen to T cell) lump
What are the two types of T cell?
CD4 and CD8
What is CTL?
Killer cells which produce molecules that can kill virus infected cells (perforin/granzyme)
What are TCR?
T cell receptors
What are CD4/CD8?
Co-receptors
What are MCH-I and MCH-II?
Major histocompatibility complex class 1 and 2
What does CD4 do?
Send chemical signals/cytokines to other cell types (B cells and CD8)
What do B cells do?
Differentiate into plasma cell which produces lots of antibody
What does CD8 do?
Make CTL killer cells
What do perforin/granzyme do?
Cause lysis of infected cells (virus/cancer)
What is an antigen?
Anything that has the potential to be recognised by the immune system
What is a foreign antigen?
Anything from outside- transplants, pathogens and some chemicals
What is auto (self)-antigen?
Immune system is normally tolerant of self-antigen. Self-antigen may be recognised in autoimmune disorders (rheumatoid arthritis or type 1 diabetes)
What is the purpose of antigen uptake (innate response)?
Clearance of pathogens
What is the purpose of antigen uptake (adaptive response)?
For presentation to T cells
when did adaptive immunity evolve in vertebrates?
500 million years ago
Why did phagocytes evolve?
To keep remnants of pathogens and display these to other cells of the immune system (beginning of adaptive immune response)
What do invertebrates have?
Innate immunity only
What do vertebrates have?
Both innate and adaptive systems
What do jawless fish have?
They are vertebrates with both innate and adaptive systems but their adaptive system is based off different structures compared with other vertebrates
What happens with peptides from antigens?
They are loaded onto MHC molecules for immune surveillance (waiting to be recognised by T cells)
What does MHC-I present?
Endogenous (intracellular) antigen
What is MHC-I expressed on?
All nucleated cells (not red blood cells as they don’t have a nucleus)
What does MHC-II present?
Exogenous (extracellular) antigen
What is MHC-II expressed on?
Only on antigen presenting cells
What happens first in MHC-I antigen processing?
Antigenic proteins are degraded to peptides in cytoplasm
What happens after antigenic proteins are degraded to peptides in the cytoplasm?
Peptides are imported into endoplasmic reticulum (ER)
What happens after peptides are imported into endoplasmic reticulum?
Peptide loading of MHC-I takes place in ER
What happens first in MHC-II antigen processing?
Antigenic proteins are degraded in acidic phagolysosome
What happens after antigenic proteins are degraded in acidic phagolysosome?
Peptide loading of MHC-II takes place in phagolysosome
