B cell production and activation part 1 Flashcards
Germinal centers are structures located in ____ where several steps of T-?___ humoral immune response occurs
secondary lymphoid organs.
T-dependent
this specialized type of helper T cell facilitates the formation of germinal centers
Follicular helper T cell.
activated B cells differentiate into Ab-secreting plasma cells in which kind of T cell response?
T-cell dependent
T-independent responses are elicited by engagement of ?
BCR
isotype switching and affinity maturation are typically seen in?
Humoral immune responses to protein antigens.
T-cell Dependent signals drive?
isotype switching and affinity maturation
naive B cells are stimulated by Antigen to become activated and differentiate in Plasma cells that produce specific antibodies to the antigen in this immune response stage?
Primary
this immune response is elicited when the same antigen stimulates memory B cells leading to a greater production of specific antibodies.
secondary
Long-lived plasma cells are located in the?
bone marrow
in primary response, which antibody usually has higher presence?
IgM
in secondary response, which antibody is increased?
IgG. under certain conditions you can switch to IgA or IgE.
T-independent responses to multivalent antigens are mediated mainly by?
Marginal zone B cells in the spleen and B-1 cells in mucosal sites.
T-independent responses involve which type of antibody?
IgM from short-lived plasma cells
T-dependent involves which type of antibody response?
isotype switching with high affinity antibodies from long-lived plasma cels
large antigens are delivered by?
subcapsular sinus Macrophages or by DC’s in the splenic medulla
small antigens are delivered to?
B cells in follicles through AFFerent lymphatics via conduits.
VDJ recombination occurs ?
in the bone marrow. a primary lymphoid organ.
follicular B cell survival depends on signals from?
BCR and cytokine BAFF (B cell activating factor from the TNF family)
Myeloid cells produce ___ in lymphoid follicles in the bone marrow
BAFF
BCR 1 initiates…
B cell activation process
BCR 2 functions in?
internalizing bound Antigen into endosomal vesicles.
how are B cells restricted?
…..
B cell activation is facilitated by?
CR2-CD21 coreceptor on B cells
non-microbial polysaccharides can activate complement which is one of the reasons that such antigens are able to?
induce antibody response without T cell help.
naive B cells that are activated by antigen recognition can migrate from the follicle toward T cells as a result of the expression of?
CCR7
in germinal centers, which events occur?
somatic maturation, affinity maturation, isotype switching, generation of memory B cells from long-lived plasma cells.
B cell - T cell interaction in extrafollicular sites lead to isotype switching and short lived plasma cell generations which induce?
follicular helper T cells
B cells can recognize
linear peptides that bind to conformational epitopes specific for the peptide antigen.
helper T cells that are activated by antigen recognition presented by B cells express?
CD40L
ABO blood group antigen is a type of polysaccharide that can
activate B cell antibody production without the help of T cells
CD40L mutations are?
X-linked recessive involving only Males affected.
in T-independent responses, which specialized T cells help?
Extrafollicular helper T cells.
secondary follicles are located ____ and involve T-dependent cells
in germinal centers
high affinity maturation occurs with?
T-dependent responses
Bcl-6 is a type of B cell transcription factor associated with?
T-dependent responses.
dark zones of germinal centers contain
proliferating B cells
light zones of germinal centers contain?
follicular DC’s
activated B cells migrate into the follicle expressing CCR7 and proliferate thus creating?
a Dark zone
B cells in the dark zone undergo extensive?
isotype switching and somatic hypermutation of Ig V genes
B cells with the highest affinity of Ig receptors are selected to survive to differentiate into?
plasma cells and memory cells
plasma cells leave and reside where?
in the bone marrow as “long-lived plasma cells”
memory B cells will enter the
recirculating lymphatics
Follicular helper T cells express?
ICOS, PD-1, IL-21, and Bcl-6 which play important roles in activation of B cells.
which cytokine is secreted by Tfh cells and is required for GC development and generation of plasma cells?
IL-21
follicular helper T cells secrete IFN-gamma and IL-4 to control?
isotype switching
