Immunology Flashcards
git good (37 cards)
What is the initial response to a pathogen breaching defences due to injury?
Inflammation - pain, heat, redness, swelling
What are the main features of the lymphatic system?
Lymphatic vessels - lines that connect the system, Nodes - a point in the network at which lines or pathways intersect, Lymph - A colourless fluid containing white blood cells that drains through the lymphatic system into the bloodstream
What are the organs involved in the lymphatic system?
Thymus, Spleen, Lymph Nodes
What are some anatomical points of the lymph nodes?
Blood enters through the artery and branches into germinal centres, it leaves through the vein. Lymph enters through an afferent lymph vessel to meet the blood before draining back out the other side.
Name some prominent adaptive white blood cells..
B cells, T cells
Name some prominent innate white blood cells..
Macrophages, Phagocytes, Dendritic cells, neutrophils
What is a complement?
A cascade of proteins in serum which are activated by antibodies or molecules from pathogens and amplifies the inflammatory response. Can directly kill pathogens or attract immune cells.
Describe neutrophils
The most prominent WBC
Are activated by phagocytic cells
Consume and kill pathogens
Brought into tissues by inflammation
They are short lived, innate
Describe macrophages
Develop in tissues from precursors
Are active phagocytic cells - Consume and kill pathogens.
Activated by inflammation
Are long-lived.. they are innate
Describe dendritic cells
Develop in tissues from precursors
Are active phagocytic cells
migrate out of peripheral tissues (not of primary concern to the function of a particular organ.)
carry proteins to lymph nodes
active adaptive immune response
Define the innate immune system
Limited specificity
Found in all tissues especially at barrier sites
Acts quickly following infection, limited memory
Describe the adaptive immune system
Specific for particular proteins/antigens
Mainly found in lymphoid organs
Takes 5-10 days to get going
Long-lived immune memory
Protein antigens can be broken down to form what? (specificity)
peptide chains: we also call this the antigen or epitope
What are the main 3 kinds of cells that specifically recognise antigens via specialised surface receptors
B cell receptor (BCR)
T cell receptors (TCR) - the CD4 and CD8
How do B cell receptors work and what do the cells do?
binds to native proteins/antigens
No accessory cells required
Make antibody to clear up pathogen
How do T cells work?
T cells recognise processed antigen presented on MHC molecules on the surface of antigen presenting cells
What are the differences between CD4 and CD8 cells
CD4 T cells see longer peptides in MHC class II molecules, recognise peptides presented on MHCII molecules
MHCII is mainly expressed by Professional Antigen Presenting Cells: B cells, macrophages and DCs. Co-ordinate immune response
CD8 T cells see short peptides in MHC class I molecules recognise peptides presented on MHCI molecules
MHCI is expressed by all nucleated cells: e.g. B cells, macrophages, DCs, epithelial cells and fibroblasts, Kill infected cells
Where are adaptive immune cells generated?
Primary organs: thymus and bone marrow
Where are adaptive immune cells activated ?
Secondary lymphoid organs:
Lymph nodes and spleen
What are the antibodies that can be produced by B cells?
IgM, IgG, IgE, IgA
What does IgM do?
low affinity antibody with high avidity
What antibody is most abundant in serum?
IgG
What does IgE do?
Involved in allergy and anti-helminth worm responses
Where is IgA found?
Found at mucosal sites
