Ch. 42 The Immune System Flashcards
pathogen
organism/ virus, that causes disease
host
organism invaded by pathogen
antigens
substances that can ellicit a response from a B and T cell
epitope
the small accessible part of an antigen that binds to an antigen receptor
T cells
lymphocytes that migrate and mature in the thymus
bind to antigen fragments presented on an antigen presenting cell
B cell
lymphocytes that mature in bone marrow
antigen receptor
part of a B or T cell that binds to the antigen
antibody
a protein secreted by plasma cells that bind to a particular antigen
secreted by B cells
APC
antigen presenting cell, immune that engulfs the pathogen and break it down
MHC
major histocompatibility complex,
molecules are host proteins within the APC that display the antigen fragments on the cell surface
active immunity
occurs naturally when a pathogen infects the body
antigens intro through vaccines
passive immunity
immediate, short term protection (nursing baby)
innate immunity response
found in all animals and plants
recognition and response rely on traits common to groups of pathogens
phagocytic cells in mammals
neutrophils
macrophages
neutrophils
circulate in the blood and are attracted by signals from infected tissues
macrophages
found throughout the body
interferons
provide innate defense interfering with viruses and helping activate macrophages
adaptive immune response
receptors provide pathogen specific recognition
relies on two types of lymphocytes (white blood cells)
lymphocytes migrate and mature in thymus above the heart and are called
T cells (cell mediated immunity)
B cells (humoral/ blood immunity) found in
bone marrow
once activated, B and T cells
undergo multiple cell divisions to produce a clone of identical cells (clonal selection)
types of clones produced
short lived- activated effector cells that act immediately against the antigen
long lived- memory cells that can give rise to effector cells, if the same antigen is encountered again
immunological memory
first response to a specific antigen represents the primary immune response
during this time B and T cells give rise to their effector forms
in the secondary immune response
memory cells facillitate a faster, stronger and longer response
antibodies do not kill pathogens, they mark them for destruction
B cells trigger themselves
Helper T cells trigger B and cytotoxic T cells
