The Immune System: specific immunity Flashcards
where are T cells produced
bone marrow as immature
where do T cells mature
thymus gland, under the influence of thymosin, becomes specialised
how do T cells become activated and what happens after
encounter infective connective tissue
travel around the bloodstream only attacking when they recognise the one specific antigen
where are B cells produced and matured
bone marrow
describe the function of B cells
produce antibodies/immunoglobulins, targets one specific antigen
define immunoglobulins
glycoproteins that bind and destroy antigens
describe T cells and the cell mediated response
encounter an antigen for the 1st time, they become sensitised to it
cannot detect free antigens in body fluids
so need antigen-presenting cells (APCs) to present the antigen
describe an APC
macrophage
engulf and digest antigen
presents antigen on plasma membrane
describe a cytotoxic T cell (CD8)
inactivate antigen carrying cells by releasing a toxin
destroy abnormal body cells
define abnormal in relation to the immune system
infected or cancerous
describe T helper (CD4)
produce cytokines (interleukins/interferons) to support and promote CD8 cells and macrophages
stimulate B cells to produce antibodies
describe T regulatory cells
turn off activated T and B cells
limiting the immune response’s potentially damaging effects
immunological tolerance
define immunological tolerance
preventing the development of autoimmunity and to protect the fetus during pregnancy
describe T memory cells
respond rapidly to followoing encounters with the same antigen
describe B cells and the antibody mediated (humoral) immunity
B cells recognise and bind to antigens directly
make antibodies, some released into the bloodstream for distribution but also B cells present antibody on plasma membrane
Helper T cells enable the B cells to enlarge and multiply making 2 B cells: Memory B cells
Plasma cells
define plasma cells
produce antibodies, that bind to and destroy the antigen
define memory B cells
provides long term immunity for that antigen
define antibodies
glycoproteins, in immunoglobulins group
bind to antigens
bind to toxins, neutralising them
activate complement
describe the function of IgA
covers epithelial membrane to prevent antigens crossing over
found in breastmilk and saliva
describe IgD function
made by B cells
displayed on B cells plasma membrane
antigens bind to activate B cells
describe the function of IgE
found on plasma membranes
triggers inflammatory response by binding to an antigen
describe IgG function, Grandmas live longer
longest-lived
attacks many different pathogens and crosses the placenta to protect fetus
describe the function of IgM, mothers born recently
sign of recent invasion
short lived, appear first
activator of complement system
describe the general structure of an antibody
two heavy amino acid chains
two light polypeptide chains
binds between chains is disulphide bonds
describe the complement system
system of 20 proteins found in blood and tissues
activated by presence of anitgen-antibody immune complexes
binds to, and damages bacterial cell walls
binds to bacterial cells walls, stimulating phagocytosis
attract phagocytotic cells to the area of infection
