7th Page Flashcards
What are the 5 surface markers of B cell maturation?
CD19, CD45R, CD43, CD24, and C-kit
What intracellular proteins are involved in B cell maturation?
TdT, RAG-1, and RAG-2
TdT means
Terminal deoxyribonucleotide transferase
RAG-1 and RAG-2, what does RAG mean?
Recombination-activating gene
Code for enzymes involve in gene rearrangement
TdT, RAG-1, RAG-2
What is the role of C-Kit on pro-B cells?
C-Kit interacts with stem cell factor (cell surface molecule) found on stromal cells.
What gene rearrangement occurs in B cell maturation?
Rearrangement of genes on chromosome 14, coding for the heavy-chain part of the antibody molecule.
What occurs during the Pre-B cell stage?
Synthesis of the heavy chain part of the antibody molecule occurs.
What is the first heavy chain synthesized in Pre-B cells?
The mu (μ) chain, which belongs to the IgM class.
This chain accumulate in the cytoplasm.
What is a characteristic of Pre-B cells regarding light chains?
Pre-B cells may express mu chains on the cell surface along with a Surrogate Light Chain.
Surrogate Light Chain- unusual light chain molecule
What indicates the rearrangement of genetic sequences in immature B cells?
The appearance of complete IgM molecules on the cell surface.
(coding for light chains one either Chromosome 2 or 22 has take place this time)
receptor for a breakdown product of C33, known s C3d
CD21
They are important for interaction of B and T cells
CD4 MHC Class II
(CD4 is primarily a surface marker found on a subset of T cells known as CD4+ T cells)
What are the other surface proteins expressed by Pre-B cells?
CD21, CD40, and MHC class II
They remain in the spleen to respond quickly to blood-borne pathogens.
Marginal zone B cells
These cells migrate to lymph nodes and other secondary organs
Follicular B cells
What are the surface markers of mature B cells?
IgM and IgD
What is the surface marker of activated T cells?
CD25 (also found on active T cells)
Receptor for IL-2
CD25 is the receptor for:
IL-2
CD25 is the alpha chain of the IL-2 receptor
characterized by abundant cytoplasmic Ig and little to no surface Ig
plasma cells
cell that produces antibodies
plasma cells
They are not normally found in the blood but are located in germinal centers in peripheral lymphoid organs
Plasma cells
What is the role of antigen-independent activation in B cells?
Bone marrow is involved in antigen-independent activation of B cells.
Where does antigen-dependent activation in B cells take place?
primary follicles of peripheral lymphoid tissue
Follicular dendritic cells role in antigens
present antigen to B cells and thus play a key role in the immune response
Sequence of B cells
Immature to Mature to Activated resulting to Effector B/Plasma cells and memory B cells
interleukins that help in the differentiation of B and T cells
IL-7
kappa (κ)
K2
chromosome 2
Kappa light chains are one of the two types of light chains that can be paired with heavy chains to form antibodies.
lambda (λ)
L22
chromosome 22
The lambda light chain genes are located on chromosome 22.
second type of light chains found in antibodies.
What are examples of T-Independent antigens?
plant lectins
polymerized protein
lipopolysaccharides in bacterial cell walls.
What is the result of T-Independent antigen activation?
produce IgM only because the induction of memory cells does not occur to any great extent.
What are the stages of B cell development?
Pro-B cell
Pre-B cell
Immature B cell
Activated B cell
Mature B cell
Plasma cells
What are the surface markers associated with Pro-B cells?
Surface markers include c-Kit, CD45R, CD19, CD24, Ig-alpha/Ig-beta, IL-7R, CD43, CD25, mIgM, and mIgD.
B cells can be activated to produced:
T-Dependent and T-Independent Antigens
T-Independent Antigens
Able to interact with multiple imunoglobins receptors on B cells to cross-link them and induce proliferation sand antibody productioj
T-Dependent Antigens being activated
T helper cells bind to the B cell through antigen receptor and through CD40 on the B cell and CD40L on the activated Th cell.
Guess what Ig: Secondary
G2
IgG
Guess what Ig: Chronic
IgG
Guess what Ig: anamnestic
IgG
anamnestic refers to a type of immune response that occurs upon re-exposure to an antigen that the immune system has previously encountered
Guess what Ig: primary
IgM
Guess what Ig: warm
IgG
Guess what Ig: acute
IgM
Guess what Ig: cold
IgM
Guess what Ig: cold-reacting antibody
IgM
Guess what Ig: agglutinating
IgM
Guess what Ig: non-agglutinating
IgG
