18, B cells and immunization

humoral or antibody mediated

what part of the adaptive immunity are B cells

secretion antibodies and cytokines

what are the major functions of b cells

bone marrow

where do colonal selection of b cells occur

spleen, lymph nodes, MALT

where are matured b cells primairly found

b cell receptors BCR

what do b cells express on their cell membrane

one

how many types of BCR does each b cell generate

one

how many epitopes does each BCR recognize

one

how many antibodies can each b cell process

membrane bound

what is the difference between antibodies and BCR

10^11

how many different antibodies can we synthesize/ different b cells

genetic rearrangement of hundreds of gene receptors

what enables diveristy of receptor specificites

discrete loci

where do genes for constant and varibale regions of BCR occur

VH variable, DH diversity, JH junction segments

what is the orginization of the varibale region of heavy chain

VL variable, JL junction segments

what are the varibale region of light chain variable locus

RAG enzyme

what combines different variable region segments to generate diversity

randomly combines D with J, then DJ with V, transcription and translation BCR

steps of how RAG works

b cell activated directly, short response

t cell independent antibody production

b cell activated by antigen in combination with Th, extended resposnse

t cell dependent antibody production

t independant antigens cross link multiple BCRs

how are B cells activated in independant antibody production

clonal expansion and differentiation into plasma cells

what occurs after b cells are activated in independant antibody production

plasma cells

majority of cells produced during B cell proliferation

secrete antibody complementary to antigen

what do plasma cells do

antibodies and progeny persist

what occurs after plasma cells die after a few days of activation

different antibodies

what does each plasma cell produce

antigen presentation for Th activation and proliferation

step one of t dependent antibody immunity

MHC 2 epitope of antigen presenting cell

what does TCR of Th cell recognize

immunoloigcal synapse

what forms after cell to cell contact site between Th and APC

differentation of helper t cells into th2 cells

step 2 dependent antibody immunity

interleukin 4 IL4

what acts as signal to Th cells to become Th2 cells

activation of b cells

step 3 t dependnet antibody immunity

linked recognition

what is coordination between b cells and Th cells called

MHC 2 eptiope complex

what forms on the surface of bcell when antigen binds to BCR

th2 cells with TCR epitop

whatbinds to the MHC 2 eptiope complex of b cells

proliferation and differentiation of b cells

step 4 dependant antibody immunity

cytokine secretion of Th cells

what stimulates b cells to proliferate (clone)

memory cells and plasma cells

what do proliferation of b cells form

cytokine secretion by th2 cells

what stimulates celass switch of B cells (mainly to IgE)

IgM molceules

what do all b cells in bone marrow have displayed on their surface

IgD molecules as membrane bound antigen receptors

what do b cells make after leacing the bone marrow

b cells secrete IgM antibodies

activation via t cell independant antibody production

secondary classes of antibody (Ig A E, G

what does activation of Th cells trigger class switch to (essential for secondary immune resposne)

secondary class antibodies

b cells switch from making IgM to one of what

class switch recombination

deletion of all CH coding sequences between VDJ coding and particular CH coding sequence that the cell is destined to express.

antigen stimulation dependent on th cells and cytokines

when does B cell class switching occur

BCR complementary to their epitope

what do memory cells hace that trigger their production

b cell proliferation

what produces memory cells n

no

do memory cells secrete antibodies

lymphoid tissue and bone marrow

where do long lived memmory cells presist

antibody production

what do memory cells iniitiate if antigen is encountered again

active immunity

activation of an individuals own adaptive immune defences

passive immunity

transfer of adaptive immune defenses from another individual or animal (ex. mom and baby)

naturally acquired

repsone after antigen encounter in daily life

articficial acquired

reponse to antigens introduced via a vaccine

herd immunity

suscetible individuals protected by those who are vaccinated

small pox

what was the first kind of vaccination developed in asia for

variola virus

what causes the highly infectious small pox