PCB 3233 EXAM 5 STUDY GUIDE
KNOW THE DIFFERENT CELLS THAT CAN BECOME PLASMA CELLS. - correct answer ✔✔-activated B cells
-isotype switched, somatically hyper mutated centrocytes
-memory B cells
What are the components of the B cell co-receptor ( CR2 is one of them) - correct answer ✔✔-CR2:
complement receptor-2: binds to complement deposited on the pathogen
-CD19: receptor signaling
-CD81/TAPA-1: binds to CD19 and is essential and bringing it to the B cell surface
What does CR1 do for the co-receptor - correct answer ✔✔CR1 binding to C3b on a pathogen facilitates
the cleavage by factor I to ic3b and C3d, then the CR2 component of the B cell co-receptor binds to C3d
What does TI antigen mean? What makes these different than TD antigens? - correct answer ✔✔-TI
stands for Thymus Independent . They activate production of Cells without T lymphocyte involvement
-TD antigens are Thymus Dependents AGs. Bulk of pathogens specific AB are produced by TD AGs. TD
AGs are activate B cells in the secondary typhoid tissues.
Describe B cell activation, CD40 ligand, CD40, NFkB, ICAM-1 and IL-4 secretion by T cells. - correct answer
✔✔-Once B cells meet their antigen, the BCR and the co-receptor CXCL-13 calls B cells to follicle. CCL-
19/CCL-21 calls into the lymph nodes. These changes TRAP the B cell in the Cell area close to the B cell
zone. This allows for effector T-cells to test their TCRs against the AG-MHC II on the B cell--> cognate
interactions and conjugate pairs.
-CD40 ligand expressed by T cells, to bind to CD40 on the B cell. Activates TF NFkB. NFkB increases
expression of adhesion molecule ICAM-1 to strengthen the adhesion between the two cells.
-IL-4 is secreted by the T helper cells and allows for centrocyte differentiation into memory B cells.
Define Follicular dendritic cells - correct answer ✔✔FDC are non-lymphoid cells of follicles in secondary
lymphoid tissues. Their long branching points make contact with B cells-they also have Fc and
complement receptors that hold Ag":Ab complexes on their surfaces. These cells are crucial in selecting
Ag-binding B cells during Ab response.
, Define dark zones in follicular dendritic cells - correct answer ✔✔In the dark zones, there are closely
packed centroblasts and FDCs secrete those below for proliferation:
1. IL-6
2. IL-15
3. 8D6
4. BAFF
Define light zones in follicular dendritic cells - correct answer ✔✔In the light zones, slowly to non-
dividing centrocytes will interact with antigens held by FDC's
what is in each of the zones? - correct answer ✔✔-Dark zone: there are FDCs which secrete IL-6, IL-5,
8D6, and BAFF to proliferate.
-close packed proliferating centroblasts and T cells
-T follicular helper cells attached to B -cells interacting with CD40 induce B cells to make AID --> somatic
hypermutation and biotype switching
What happens to the cells in the zones? - correct answer ✔✔-Centrocytes move from GC dark zone--
>capture antigen from FDC--> moves to GC light zone outer regions to helper T cells
-In dark zones:
1. 80% centroblasts
2. Rapidly dividing activated B cells
3. Going through somatic hypermutation and isotope switching
4. No BCR on surface
5. B cells secrete AID
-In light zone: 10-20% centrocytes
a. slowly non-dividing B cells with mutated , isotope switched BCR
b. express BCR again to test against antigen
KNOW THE DIFFERENT CELLS THAT CAN BECOME PLASMA CELLS. - correct answer ✔✔-activated B cells
-isotype switched, somatically hyper mutated centrocytes
-memory B cells
What are the components of the B cell co-receptor ( CR2 is one of them) - correct answer ✔✔-CR2:
complement receptor-2: binds to complement deposited on the pathogen
-CD19: receptor signaling
-CD81/TAPA-1: binds to CD19 and is essential and bringing it to the B cell surface
What does CR1 do for the co-receptor - correct answer ✔✔CR1 binding to C3b on a pathogen facilitates
the cleavage by factor I to ic3b and C3d, then the CR2 component of the B cell co-receptor binds to C3d
What does TI antigen mean? What makes these different than TD antigens? - correct answer ✔✔-TI
stands for Thymus Independent . They activate production of Cells without T lymphocyte involvement
-TD antigens are Thymus Dependents AGs. Bulk of pathogens specific AB are produced by TD AGs. TD
AGs are activate B cells in the secondary typhoid tissues.
Describe B cell activation, CD40 ligand, CD40, NFkB, ICAM-1 and IL-4 secretion by T cells. - correct answer
✔✔-Once B cells meet their antigen, the BCR and the co-receptor CXCL-13 calls B cells to follicle. CCL-
19/CCL-21 calls into the lymph nodes. These changes TRAP the B cell in the Cell area close to the B cell
zone. This allows for effector T-cells to test their TCRs against the AG-MHC II on the B cell--> cognate
interactions and conjugate pairs.
-CD40 ligand expressed by T cells, to bind to CD40 on the B cell. Activates TF NFkB. NFkB increases
expression of adhesion molecule ICAM-1 to strengthen the adhesion between the two cells.
-IL-4 is secreted by the T helper cells and allows for centrocyte differentiation into memory B cells.
Define Follicular dendritic cells - correct answer ✔✔FDC are non-lymphoid cells of follicles in secondary
lymphoid tissues. Their long branching points make contact with B cells-they also have Fc and
complement receptors that hold Ag":Ab complexes on their surfaces. These cells are crucial in selecting
Ag-binding B cells during Ab response.
, Define dark zones in follicular dendritic cells - correct answer ✔✔In the dark zones, there are closely
packed centroblasts and FDCs secrete those below for proliferation:
1. IL-6
2. IL-15
3. 8D6
4. BAFF
Define light zones in follicular dendritic cells - correct answer ✔✔In the light zones, slowly to non-
dividing centrocytes will interact with antigens held by FDC's
what is in each of the zones? - correct answer ✔✔-Dark zone: there are FDCs which secrete IL-6, IL-5,
8D6, and BAFF to proliferate.
-close packed proliferating centroblasts and T cells
-T follicular helper cells attached to B -cells interacting with CD40 induce B cells to make AID --> somatic
hypermutation and biotype switching
What happens to the cells in the zones? - correct answer ✔✔-Centrocytes move from GC dark zone--
>capture antigen from FDC--> moves to GC light zone outer regions to helper T cells
-In dark zones:
1. 80% centroblasts
2. Rapidly dividing activated B cells
3. Going through somatic hypermutation and isotope switching
4. No BCR on surface
5. B cells secrete AID
-In light zone: 10-20% centrocytes
a. slowly non-dividing B cells with mutated , isotope switched BCR
b. express BCR again to test against antigen
