L6: Immune System Overview Flashcards
What is an antigen?
A molecule capable of inducing an immune response. Often found on microbes.
Name the primary lymphoid organs.
Thymus, bone marrow.
Name the secondary lymphoid organs.
Spleen, lymph nodes.
The spleen has distinct B cell and T cell areas. Name some.
Periarteriolar lymphoid sheath (PALT) = T cells.
Marginal zone = B cells.
Two key functions of macrophages (innate)?
Phagocytosis and inflammation (secrete cytokines and chemokines).
Define ‘phagocytosis’.
The engulfment of a cell/particle following recognition by a viral membrane receptor.
Define ‘inflammation’.
The physiological response of the body to injury that begins the healing process.
Function of neutrophils?
They are phagocytic. They are also granulocytes - they possess granules in their cytoplasm. They rapidly migrate to sites of inflammation and release their toxic granules.
What is an epitope?
A specific part of an antigen that is recognised by a BcR/TcR.
What type of epitope does a B cell bind to?
Conformational and linear epitopes.
What type of epitope does a T cell bind to?
Linear epitopes (short peptides).
Key role of DCs?
To link the innate and adaptive immune responses. They are APCs that recognise PAMPs, take up pathogen proteins and digest them into peptides which can then be presented on MHC Class I/II. Migrate from the peripheral tissues to the lymph node where they active naive adaptive immune cells.
