Cell-Mediated Response Flashcards
What are T cells/lymphocytes?
a white blood cell that causes a cellular response to infection
Where are T cells produced?
made in the bone marrow and mature in the thymus gland
What is the structure of T cells?
has receptor proteins on its surface to bind to complementary antigens presented to it by phagocytes (activates the T cell)
What is the function of T cells?
destroy self cells that have unfamiliar antigens on their surface including:
- infected body cells (by virus or mutated)
- a macrophage that is presenting engulfed antigens
- cancer cells
- cells of transplanted organs
Why is it called cell - mediated response?
T cells only respond to antigens which are presented on cells (APC) and not antigens detached from cells and within body fluids e.g. blood
What is the cell-mediated response?
1.) once a pathogen has been engulfed + destroyed by a phagocyte, the antigens are on the cell surface - now an APC.
2.) Helper T cells have receptors on their surface which can attach to the antigens on the APC.
3.) once attached, this activates the helper T cells to divide by mitosis to replicate and make a large number of clones.
4.) cloned helper T cells differentiate into different cells:
-some remain helper T cells and activate B cells
- some stimulate macrophage to perform more phagocytosis
- some become memory cells for that shaped antigen
- some become cytotoxic/killer T cells
- suppressor T cells stop the action of the T cells when the infection clears
How do cytotoxic/hiller T cells kill cells?
release a protein, perforin, which embeds in the cell membrane and makes a pore which allows cell contents to move out and solution to move in killing the cell.
What is the cell-mediated response/cytotoxic cells most effective against?
viruses as they live inside cells and needs living cells to reproduce - body cells are sacrificed to prevent viral replication.
