B cells encounter Ag Flashcards
B cell home to LN via what
HEV
what do b cells use to enter t cell zone
CCL21 and CCL19
what do b cells use to move to the b cell zone
CCL13
where do b cells move to to interact with macrophage
b cells move subcapsular sinus to interact with macrophage
once b cells move to subcapsular sinus to interact with macrophage and it binds ag what happens
b cells express CD69 to retain S1PR inside the cells-> prevents B cells from leaving LN.
is B cells dont interact with the macrophage it will move to
follicle and interacts with FDC
if b cell moves to follicle and interacts with FDC and binds Ag what happens
b cells express CD69 to retain S1PR inside the cells-> prevents B cells from leaving LN.
if the b cell moves to follicle and interacts with FDC and doesn’t bind Ag what happens
B cell follows S1P gradient and leaves LN. and goes back to the beginning
Once B cells express CD69 to retain S1PR inside the cells and prevents B cell from leaving LN what happens next
B cell endocytose Ag and present it on MHCII
once the B cell endocytose Ag and present it on MHCII what happens
B cell expresses CCR7 and moved to B/T cell boundary
once the B cell expresses CCR7 and moved to B/T cell boundary what happens
B cell forms a cognate pair with TFH cell which bind both the same Ag
once B cell forms a cognate pair with TFH cell what happens
CD40L binds CD40-> induces NF-KB
NF-KB does what
upregulates adhesioin molecules
Once CD40L binds CD40-> induces NF-KB what happens
B cell expresses ICAM-1 which binds LFA-1 on the T cell
once B cell expresses ICAM-1 which binds LFA-1 on the T cell what happens
TFH cell delivers cytokines directly on the surface of the B cell
once TFH cell delivers cytokines directly on the surface of the B cell what happens
B cell proliferate to form primary focus
what is subset 1 once b cells proliferate to form primary focus
B cell becomes IgM plasma cell and secretes IgM
what is subset 2 once b cells proliferate to form primary focus
continue differentiation
once B cells proliferate to form primary focus what happens
B cells move to primary follicle
what happens in the primary follicle
becomes germinal center
what does the light zone contain
FDCs B cell undergoes affinity maturation
what survives in affinity maturation
strongest binder survives
what is the dark zone
densely populated and is where B cells proliferate and undergo somatic hypermutation
what cells use somatic hypermutation
TFH
process of somatic hypermutation
activate AID-> which introduces mutations and then each proliferate the B cell and gets differentiation mutations and if they express mutated BCR they move to the light zone
affinity maturation uses what cells
FDCs
what are in affinity maturatioin but are not quite a plasma cell
centrocytes
in affinity maturation: bind better to Ag results in
survival signals from FDC
in affinity maturation: bind equal to Ag results in
die by apoptosis
in affinity maturation: bind less to Ag results in
die by apoptosis
in affinity maturation: bind self results in
induce anergy
what cells are used in class switching
TFH
what do TFH cells secrete in class switching
cytokines
When TFH cells secrete cytokines in class switching what is it doing
tell B cell which Ab to make
low level transcription in class switching does what
opens up locus
what mediates class switching
AID
what does class switching require
CD40-CD40L interacting signals
CD40L deficiency results in
hyper IgM syndrome
hyper IgM syndrome results in
not being able to make germinal centers and only IgM plasma cells
after B cell moves to primary follicle what happens
B cell differentiates into plasma cell and memory B cells
plasma cells stay where and secrete what
in lymph node and secrete Ab
are plasma cells short or long lives
short
when plasma cells move to bone marrow and secrete Ag are they long or short lived
long lived
memory b cells are very long or short lived
long
memory b cells differentiate into
plasma cells after interaction with Ag
