3.6 Flashcards
what are lymphocytes
wbc involved in the specific immune response
how do lymphocytes work
they respond to specific antigens on invading pathogens
what are antigens
molecules, often proteins, located on the surface of cells they trigger a specific immune response
what receptors do lymphocytes have
a single type of membrane receptor which is specific for one antigen
what does antigen binding lead to
repeated lymphocyte division resulting in the formation of a clonal population of identical lymphocytes
what do b lymphocytes do
produce antibodies against antigens
what do b lymphocytes cause
the destruction of the pathogen
what are antibodies
y shaped proteins that have receptor binding sites specific to a particular antigen on a pathogen
how do antibodies work
they bind to antigens inactivating the pathogen
how is the antigen-antibody complex destroyed
phagocytosis
what causes an allergic reaction
when b-lymphocytes response to antigens on substances that are harmless to the body (eg pollen)
what do t lymphocytes do
they destroy infected body cells by recognising antigens of the pathogen on the cell membrane and induce apoptosis
how do t lymphocytes work
they attach into infected b-cells and release proteins that diffuse into the infected cells and cause the production of self destructive enzymes which cause cell death
how are the remains of the cells destroyed by t lymphocytes removed
by phagocytosis
what does failure of the regulation of the immune system lead to
t lymphocytes responding to self antigens and causing autoimmune disease
what happens in autoimmunity
the t lymphocytes attack the body’s own cells
what are examples of autoimmune diseases
- type 1 diabetes
- rheumatoid arthritis
how are memory cells created
when some t&b lymphocytes produced in response to antigens by clonal selection theory survive long-term
what does a secondary exposure to the same antigen do
it rapidly gives rise to new clones of specific lymphocytes
what happens to antibody production during the secondary response
it’s greater and more rapid than the primary response
what does HIV do
it infects and kills t lymphocytes
what does HIV cause
depletion of t lymphocytes which leads to the development of AIDS
what do individuals with aids have
a weakened immune system and so are more vulnerable to opportunistic infections
