Q: List 5 more stages of maturation for the lymphocyte beginning with the stem cell. A: pro-lymphocyte, pre-lymphocyte, immature lymphocyte, mature lymphocyte, differentiated effector lymphocyte Q: Which stage of lymphocyte maturation takes place entirely in peripheral lymphoid organs/tissues? A: The differentiated effector lymphocyte Q: Which 4 stages of lymphocyte maturation are only found in the bone marrow/thymus under normal conditions? A: Stem cell, pro-lymphocyte, pre-lymphocyte, immature lymphocyte, mature lymphocyte Q: Where might mature lymphocytes be found (2 places)? A: Bone marrow/thymus and peripheral lymphoid organ/tissue Q: Which stages of lymphocyte development experience early maturation and growth factor-mediated expansion? A: Stem cells and pro-lymphocytes Q: At which stage of lymphocyte development are antigen receptors expressed? A: Pre-lymphocyte Q: Which lymphocyte(s) can perform effector functions (give maturational stage (s))? A: Differentiated effector lymphocyte Q: What event follows stem cell proliferation and pre-B cell proliferation during B-cell maturation? A: RAG expression Q: At what stage does recombination of the H chain gene take place? A: Pre-B cell stage Q: At what stage does recombination of light chains take place? A: Immature B cell Q: At what stage does alternative splicing of the of VDJ-C RNA take place? A: Mature B cell Q: Can Ig be expressed in the absence of H chains? A: No Q: All stages of B cell maturation have the CD43 surface marker expressed except for which stage? A: Mature B cell stage Q: How is the response of the pre-B cell to antigen different from that of an immature B cell? A: Pre- B cells cannot respond to antigen Q: Where do B cells live longer: vasculature or marrow? A: Marrow Q: Clonal expansion of B-cells results in which four events? A: Antibody secretion, isotype switching, affinity maturation, and memory B cell formation Q: Cross linking of membrane Ig by antigen directly results in what event? A: Tyrosine phosphorylation Q: Cross linking of membrane Ig by antigen ultimately results in what signals? A: Transcription factors Q: To what entity might C3d be attached? A: A microbe Q: What is the fate of C3d attached to a microbe? A: It is recognized by the B-cell CR2 receptor, and the complex, together with the Ig alpha and Ig beta complex, activates the B-cell. Q: What four changes in phenotype function occur after the activation of B lymphocytes? A: Entry into the cell cycle, increased expression of B7-1/B7-2, increased expression of cytokine receptors (IL-2, IL-4), increased survival due to expression of antiapoptotic proteins (Bcl-X) Q: What is CD28? A: It is the receptor for B7-1/B7-2 on the helper T Cell. Q: Which cell, the B-cell or the T-cell, has the CD40 ligand? A: The T-cell Q: What signals helper T-cells to stimulate isotype switching by antibodies? A: CD40 ligation, cytokines Q: What other CD activates B cells? A: CD28 Q: Without signals from helper T cells, which is the only antibody made? A: IgM Q: Is the "looping out" process reversible? A: No Q: What is the major Ig isotype secreted by the polyclonal activator LPS (lipopolysaccharide)? A: IgM Q: What is the difference between APC’s and FDC’s in terms of their location? A: APC’s migrate from tissue to lymphoid organs. FDC’s reside in the lymphoid organ. Q: How does the FDC respond to antigen? A: It binds to it but does not internalize it. Q: To what antigen do thymus-dependent antigens respond? A: Proteins Q: To what antigens do thymus independent antigens respond? A: Polymeric antigens, especially polysaccharides; also glycolipids, nucleic acid. Q: How do B cells know when to shut down? A: Antigen-antibody complexes bind to B cell Ig and Fc receptors blocking the B cell receptor signaling Q: During which B cell response to antigen is IgM the major product? A: Primary response Q: During which B cell response to antigen is there a high affinity of antibody for antigen? A: Secondary response Q: What are two ways to activate B-cells? A: T-cell dependent and T-cell independent antigen Q: CD40 is needed for which of the two pathways of B-cell activation? A: T-cell dependent B cell activation Q: Where does the T-cell see the antigen of presented by the B-cell? A: In the class II complex Q: Which are the known T-cell products that clearly stimulate B-cell proliferation? A: IL’s 2, 4, 5, and 13. Q: What do IL-2/IL-6 specifically do for B cells? A: Induce Ig secretion. Q: Chromosomal recombination is involved in which B-cell behavior? A: Isotype switching Q: What is the purpose of affinity maturation? A: To create Ig with higher affinity for antigen Q: What happens to those B cells that lose affinity for antigen? A: They are eliminated. Q: If further exposed to antigen, what response will T-cell independent antigens have? A: They will have no secondary response, and will only produce IgM isotypes of low affinity and poor quality.