Immunology 1 Flashcards
What are the primary lymphoid organs?
Thymus and bone marrow
Name 4 secondary lymphoid organs
Tonsils
Lymph nodes
Spleen
Peyers patches
What are peyers patches?
Lymphoid tissue in wall of small intestine
What is the lamina propria?
Mucose associated secondary lymphoid tissue- thin layer of connective tissue below epithilium
How long does a lymphocyte spend in an organ before it recirculates?
1-2 days
How do lymphocytes leave peripheral tissue?
They drain out of tissue as tissue fluid via the lymphatics system to the lymph nodes (afferent lymphatics)
How do lymphocytes return to the blood from the lymph nodes?
Out of lymph nodes via efferent lymphatics and back to blood mainly via thoracic duct
Name the polymorphonuclear leucocytes
Neutrophils
Eosinophils
Basophils
Mast cells
Name the granulocytes
Neutrophils
Eosinophils
Basophils
Example of anti microbial secreted mediators
Antibodies, complement proteins
Name regulatory/inflammatory mediators of immunity
Cytokines and histamine
What two things does the innate system recognise?
Pathogen associated molecular patterns (pamps) eg. Viral ds DNA and pathogen recognition receptors ( PRRs) eg toll like receptors
What is an antigen?
Anything that is recognised by a lymphocyte
What is the first immune response after skin is cut?
Immediate local innate response- complement proteins and macrophages
What is the early induced response?
Innate/inflammatory: inflammatory mediators from complement macrophages and mast cells attract leucocytes and serum proteins
What happens during the later adaptive response?
Antigen carriage by dendritic cells or freely in lymph fluid results in lymphoid tissue activation of T and B lymphocytes and antibody recirculation to site of infection
How long does it take for the adaptive immune response to kick in?
5-7 days
What is the response to extra cellular infection?
Complement proteins, phagocytes and antibodies
What is he response to intercellular vesicular infection?
Helper t-cells if macrophage can’t digest it alone
Intra-cellular cytosolic infection? Eg viruses
Interferon proteins, natural killer cells and cytotoxic cells
What is immunopathology
Diseases involving defects in or inappropriate activity of the immune system
What does the cytokines IL-6 do?
Stimulates the liver to produce and excrete acute phase protein- c- reactive pro time and man in binding lectin
What does C-reactive protein do?
C reactive protein acts as a pattern recognition protein. It binds to phosphocholine which is part of the bacterial lipopolysaccharides
What does man in binding lectin do?
Binds to mannose residues in bacterial carbohydrate
Give examples of macrophages PRRs
Mannose receptors, glucagon receptors, LPS receptors
What are toll like receptors?
Proteins expressed on macrophages and dendritic cells that recognise Structurally conserved molecules derived from microbes
How many antigen receptors and how many pamps are expressed by lymphocytes?
Millions of antigen receptors and ~100 pamps
What do you call antibody particles attached to b-cell surface?
Surface immunoglobulins (SIG)
What happens when an antigen binds to a SIG?
This triggers the B cell to become a plasma cell that secretes antibodies
True or false a B cell has thousands of SIG that all recognise the same epitope
True
What are B cells that recognise the same antigen called?
B cell clones
What do B cells do before they become a plasma cell?
They proliferate. Some stay as memory B cells
What are B cells called that have never seen an antigen before?
Naive cells
What is used for tetanus immunisation?
Tetanus toxoid (inactive but structurally identical form)
Name the two types of light chains
Kappa (k) and lambda
What are the heavy chains for IgA, IgE, IgG IgM and IgD
Mu, alpha, gamma, delta, epsilon
How many types of IgG is there and how many types of IgA?
Four types of IgG (1,2,3,4) and two types of IgA (1,2)
What is the area of an Ig that binds antigen called?
Fab: fragment antigen binding made up of one constant and variable chain of both heavy and light
What is the FC region
Fragment crystallisable region. Made up of constant heavy domains of antibody. Interact with cell surface FC receptors
How is an Ig class defined?
From constant domains of heavy chain.
How are chains held together?
By covalent bonds.
What encodes the heavy chains?
2 separate genes- 1 for variable and 1 for constant
What are B cells all originally programmed to produce?
IgM and some IgD
How many antigen combining sites does IgM have?
- It is a pentamer
Which Ig forms a secretory dimer?
IgA
Which Ig are monomers?
IgE, IgD and IgG
Where is IgM mostly found?
The blood
Where is IgG mostly found?
Blood, tissue and placental tranfer
Where is IgA and IgA dimer found?
IgA in blood and tissues and the dimer in mucosal secretions and milk.
Where is IgE found?
In tissues bound to mast cells
Where is Iga1 and iga2 mostly found?
Iga1 is mostly found in serum an iga2 is mostly found in secretions
What keeps IgM structure together?
Disulphide bonds and a joining chain
Where is IgD found
Found in membrane of immature B cells and can also be secreted in serum
