immuno chapter 6.txt

generation of diverse and clonally expressed B-cell receptors in the bone marrow

alteration, elimination, or inactivation of B-cell receptors that bind to components of the human body

promotion of a fraction of immature B cells to become mature B cells in the secondary lymphoid tissues

recirculation of mature B cells between lymph, blood, and secondary lymphoid tissues

Activation and clonal expansion of B cells by pathogen-derived antigens in secondary lymphoid tissues

Differentiation to antibody-secreting plasma cells and memory B cells in secondary lymphoid tissue

bone marrow

lymph nodes, spleen, peyer's patches

start in bone marrow and travel to secondary lymph (lymph nodes, spleen, peyer's patches)

CD34

Pro- B cell

germline configuration

heavy chain rearrangement starts

heavy chain rearrangment continues

heavy chain is made

light chain rearrangement starts

IgM on the surface

help the B cells differentiated by maintaing contact via adhesion molecules. They produce growth factors such as SCF which interacts with Kit receptor on B cells and IL-7 which helps development of the B cells

has two chances to make a productive gene or apoptosis occurs

fake light chain that acts as a place holder for the heavy chain during the Pre B cell stage

sLC and heavy chain. low amounts on the cell surface. binding a ligand means survival

assembly of pre-bcr signals the cell to stop rearrangement of the other heavy chain gene

only one recombination event requires, but several attempts happen to make a correct gene

late pro b cell stage- functional pre- BCR

small pre B cell - functional BCR

RAG proteins

compacted

x-linked disease blocking b cell developent at the pre-b cell stage so there is no circulating antibodies

signals b cell development

high activity of recombination and mutations leads to an increase chance of mistakes

different chromosomes fuse together

atypical subset of b cells that are made early in embryonic development. CD5 cell surface protein is a marker. antibodies are not diverse and tend to bind to many antigens

persist in the lymphoid tissue and can self renew

eliminate potentially self reactive B cells

b cells that bind to self antigen in the bone marrow and periphery will die or become in active.

it is retained in the bone marrow and can change its BCR

immature B cell that is expressing IgM and IgD

self reactive b cells reduce IgM and expression of rag proteins. Light chain is rearranged to make a new BCR

new BCR is not self reactive and will develop further; new BCR is self reactive and will continue rearranging until it runs out of attempts

self reactive b cells eventually die and are cleaned up by macrophages

it becomes anergic and enters the periphery to die

a homing mechanism using HEV; naive b cells bind to chemokines secreted by stomal cells.

lymphoid follicles

secrete cytokines that stimulate survival and differentiation

survival signal

differentiation signal; transforms immature B cells that enter follicle (d + m+++) to become mature b cells (d+++ m+)

they are stuck in the t cell area

entry will increase life time of cell- majority dont enter

b cells recognizing are detained in the t cell area; cd4 t cells will help activate the b cells to plasma cells

very specialized; protein synthesis and secretion is highly developed and they lose MHC II and BCR expression

activated b cells

formed by primary focus and migrates to primary follicle and then eventually becomes a secondary follicle

differentiate and reside in the medullary cords, spleen, and bone marrow

is associates with the b cell stage of the tumor

tumor of the lymphoid protenitor located in bone and blood marrow; Ig V gene is unmutated

tumor of mature memory b cell which is in the periphery and has mutated Ig v genes, and intraclonal variability

tumor of plasma cell located in the bone marrow with mutated, no ig v genes, no variability within clone