Immunology Flashcards
what are immune responses
a series of responses that ensure that when the body is invaded by any pathogen, it is rapidly identified and destroyed before too much damage is caused to the organism
what is an antigen
an antigen is a molecule (usually a protein that stimulates an immune response that results in the production of an antibody.
e.g; glycoproteins and glycolipids
what can stimulate an immune response
pathogens
toxins (often secreted by pathogenic bacteria)
transplanted cells
abnormal body cells
role of an antigen
antigens help identify each particular type of cell to the host organism
what are phagocytes
groups of white blood cells which can distinguish between cells that are self or non-self. They can also detect chemical signals produced by pathogens.
process of phagocytosis
-phagocyte engulfs the pathogen
-engulfed pathogen enters the cell in a vesicle
-lysosome fuses with the vesicle and release hydrolytic enzymes into the vesicle with hydrolyse the pathogen
-waste materials are released from the cell by exocytosis
-antigens are presented on the cell and the cell becomes an APC.
what are specific cellular responses
a specific response to a specific antigen on a pathogen that has been recognised as non-self
what is the response of T-lymphocytes known as?
cellular response
stages of cellular response
-phagocytosis
-cell becomes an APC
-T(h) cell with a specific receptor binds to the complementary antigen
-T cell is activated and clonal expansion occurs via mitosis
The cloned T daughter cells differentiate into which type of cells?
-T helper cells (release cytokines and attract other phagocytic cells to the site of infection, activates B cells)
-memory T cells
-cytotoxic killer T cells
what do cytotoxic killer T cells do
-locate and destroy infected body cells
-bind to APC
-releases perforin (which makes holes in the cell surface membrane and destroys the APC)
what is the activation of B cells known as?
humoral response
how are B cells activated?
by their complementary T cells by the release of cytokines.
B cell activation:
-specific T(h) cell with complementary receptor binds to antigen on the B cell and activates it
-T cell releases cytokines and B cell clones by mitosis
-B cell differentiate into 2 types of cells; memory cells and plasma cells (produce and secrete vast quantities of antibodies in the blood plasma)
what is the function of memory cells?
they remain in the body to respond to pathogen rapidly and extensively, should there be a future re-infection.
