L43 B Cells and Antibodies Flashcards
(22 cards)
what is specific memory characterised by?
learning
adaptability
memory
what are the components of specific immunity?
it is cellular:
- B cells (derived from bone marrow) and
- T cells (derived from thymus)
it is soluble:
- immunoglobulins (from B cells) and
- cytokines (produced by T cells)
what is the functions of B cells?
produce antibodies specific to antigen
activate T cells
activate innate immune system (complement system)
what are the functions of antibodies?
act as B cell receptors
(some antibodies are produced before antigen enters body)
The antibodies are displayed on the surface of the B cell ready to interact with the antigen
how are B cells activated?
Antibody-antigen interaction AND a second signal from another cell (both are needed)
what is clonal expansion and b cell maturation and what do they result in?
the process in which b cells divide and replicate. b cells divide into mature b cells, plasma cells, after activation. they are cloned so the antibodies produced by the plasma cells are the same
what stimulates the maturation of b cells?
cytokines
what are memory cells?
some proliferating b cells remain in the blood as memory cells. b cells remember antigen. If B cells are confronted by an antigen on a second occasion, the Ab response is much quicker (memory). forms basis for vaccination
what are the differences between primary and secondary immune responses?
Primary Response:
- Following exposure to an antigen, there is a slow rise in IgM followed by a slow rise in IgG
Secondary Response:
- Following exposure to previously encountered antigen, there is a rapid and greater rise in specific IgG (and limited rise in IgM)
- Memory or anamnestic response
- Basis for vaccination
what else do b cells act as?
antigen presenting cells, thereby stimulating the T cell arm of the immune system
what is the structure of an antibody?
contains light regions, heavy regions, antigen binding sites, constant and variable region, and disulphide bridges. look at image as reminder (OneNote)
where do antibodies bind to antigens?
blood stream or interstitial tissues. they are unable to enter cells (cant get to virus)
what are the different types of antibodies?
family of immunoglobulins (Ig), so:
IgG (4 types) IgD IgE IgA IgM
look at image of different structures (OneNote)
what are the properties of IgG antibodies?
major Ig in blood
enters tissue space
prepares bacteria to be killed
what are the properties of IgD antibodies?
found in B cell membrane
is a b cell receptor
binding of receptor helps cell division
what are the properties of IgE antibodies?
trace amount in body
high during allergic reaction
what are the properties of IgA antibodies?
2 types
- protects entrance of pathogens
- saliva, tears, GI + respiratory tract
what are the properties of IgM antibodies?
mainly in bloodstream
kills bacteria
what may be in a vaccine?
Live attenuated virus Killed virus Part of a virus Killed Bacteria Part of bacteria
what is the difference between monoclonal and polyclonal antibodies?
Monoclonal against single epitope but the epitope can be on another strand.
Polyclonal can potentially recognise multiple organisms though usually several epitopes on single organism
what is the pathology of a hepatitis B virus?
The virus has:
- Hepatitis surface antigen (HBsAg): detected in active disease.
- Hepatitis core antigen: not tested for but antibodies can be detected (HBcAb) indicating current or previous infection
name a common pathological conditions involving B cell “over-activation”
Graves’ disease (autoimmune hyperthyroidism) is production of antibodies that mimic the action of TSH (Auto antibodies that recognise receptor for TSH that stims inc production of T3 and T4 but down regulates TSH)
This leads to uncontrolled hyperthyroidism as previously discussed (refer to endocrinology)
