Specific immune system - lymphocytes Flashcards
What are lymphocytes? What are the different types of lymphocyte?
white blood cells
B lymphocytes - mature in the bone marrow
T lymphocytes - mature in the thymus gland
What are the types of T lymphocyte?
T helper
T killer
T memory
T regulator
What is the function of T helper cells?
CD4 receptors on their cell-surface membranes
these bind to the surface antigens on the APCs
they produce interleukins (type of cytokine)
What is the purpose of the interleukins?
stimulate activity of B cells - increase antibody production
stimulates production of other types of T cells
attracts and strimulates macrophages to ingest pathogens with the antigen-antibody complex
What is the function of T killer cells?
destroy the pathogen carrying the antigen
produce a chemical called perforin
perforin kills the pathogen by making holes in the cell membrane so it is freely permeable
What is the function of T memory cells?
live for a long time and are part of the immunological memory
if they meet an antigen a second time, they divide rapidly to form a huge number of clones of T killer cells that destroy the pathogen
What is the function of T regulator cells?
supress the immune system
acting to control and regulate it
they stop the immune response once the pathogen has been eliminated and make sure the body recognises self antigens and does not set up an autoimmune response
interleukins are important in this control
What are the main types of B lymphocytes?
plasma cells
B effector
B memory
What is the function of plasma cells?
produce antibodies to a particular antigen and release them into circulation
an active plasma cells only lives for a few days but produces 2000 antibodies per second while it is alive and active
What is the function of B effector cells?
divide to form plasma cell clones
What is the function of B memory cells?
live for a long time and provide immunological memory
programmed to remember a antigen and enable the body to make a very rapid response when a pathogen carrying that antigen is encountered again