Immuno Q Bank Flashcards
under what conditions do T cells become anergic?
when it interacts with APC in absence of co-stimulatory interactions (CD28/B7)
which CDs do double positive thymocytes contain?
CD2, CD3, CD4 and CD8
somatic recombination occurs for which TCR chain first? where in the body is the T cell when this occurs?
TCRB
it occurs in the thymus (cortex)
what factor activates NK cells? what cell secretes this factor? what do activated NK cells secrete and what is its role?
IL-12 activates NK cells. Dendritic cells (mostly) secrete this.
activated NK cells secrete IFNγ, which drives subset to form TH1 cells
what complements make up classical pathway C5 convertase? Alternative convertase?
classical C5 convertase: C4b2a3b
alternative C5 convertase: C3b3bBb
what are the constant regions associated with light chains?
kappa and lambda
what heavy chain constant regions exist? what antibodies do they form?
delta = IgD
mu = IgM
how many CD79a/b heterodimers are associated with a single mIg?
2
which factor initiates clonal expansion of naive CD4+ T cells? What is it secreted by and when? Where does it bind? What is this type of interaction called?
IL-2 initiates clonal expansion of naive CD4+ T cells. IL-2 is secreted by naive CD4+ T cells, after it is bound to antigen+APC.
IL-2 binds to the receptor on itself.
This is called cognate interaction.
what does C1 bind to? which results in better activation? why?
C1 binds to the Fc region of IgG and IgM
IgM leads to better activation because it is a pentamer
expression of what cytokines and adhesion molecules does macrophage secretion of IL-1 and TNFa induce?
VCAM-1, ICAM-1, MCP-1 (CCL-2), IL-8, E-selectin
what cells have FcγRI?
phagocytes; IgG binds to microbe, which then binds to FcγRI which signals the cell to perform phagocytosis
what cell is the most efficient APC?
dendritic cell
in which stage is CD20 expressed? CD19? CD40?
CD20 = Pre-B cell
CD19 = Pro-B cell
CD40 = naive/mature B-cells
which 2 cells are fused to form hybridoma?
plasma cell and myeloma cell
which antibody isotype has the highest serum concentration?
IgG
what is another name for CD154? CD152?
CD154 = CD40L
CD152 = CTLA4
what type of isotypes can be generated following switch recombination?
IgE, IgG, and IgA
which antibody exists only in membrane bound form?
IgD
what complement receptors do mast cells and basophils have?
CR3a/4a, CR5a
which is the only antibody isotype not secreted by plasma cells?
IgD
where in the body are B-cells located during VDJ recombination?
bone marrow
which antibody isotypes are associated with J chain?
IgA (dimer) and IgM (pentamer)
which isotype can cross the placenta?
IgG
what induces development of Th1 subset? Th2?
Th1 = IFNγ
Th2 = IL-4
which complement causes chemotaxis? of which cells?
C5a = neutrophils
what do Th2 cells secrete?
IL-4, IL-5, IL-6, IL-13 and TGF-B
which antibody is also known as reaginic antibody?
IgE (reaginic = allergic activity)
what does CD28 bind to? on what cell is CD28 located? what is another CD that binds to B7?
CD28 binds to B7 (CD80/86)
CD28 is located on the T cell
another CD that binds to B7 is CTLA-4 (CD152), which is inhibitory
what is the role of Properidin?
stabilizes C3bBb (C3 convertase)
which receptor is present only on B-cells? why is this significant?
CR2; path of Epstein-Barr virus infxn
what 2 factors are critical for clonal expansion? what role do they play? what happens if factors are absent?
CD28/B7 (B7 = CD80/86); triggers signal transduction that leads to mRNA stabilization for IL-2.
If these factors are absent, the T cells becomes anergic.
which complement is an anaphylatoxin not involved in alternative pathway?
C4a
what is the role of IL-8? what stimulates IL-8 secretion? from what cells is it secreted?
chemokine for neutrophils to site of injury
IL-1 and TNF stimulate IL-8 secretion
IL-8 is secreted by endothelial cells and macrophages
what does pCTL bind to in order to induce CD8+ T cell activation? What other factor is required for activation?
pCTL binds to Class I MHC on autologous cell; IL-12 is required for activation
what do active phagocytes primarily secrete? what is the main purpose of cytokine release?
TNF, IFNγ
Bring about inflammation by synergistically stimulating other macrophages
which 2 isotypes are involved in isotype switching to form all other isotypes? where in the body does this occur?
IgM, IgD
it occcurs in the germinal center
which cytokine is critical for T cell selection?
IL-7
what CDs do single positive T cells have? what other receptors?
CD2, CD3, CD4 OR CD8 (not both)
TCR
which antibody isotypes are found in milk and colostrum? Which is the most prominent?
IgA, IgM, IgG
IgA is the most prominent
what cells is RAG-1 and RAG-2 expressed in?
pro- and pre-B-cells and T-cells
which cytokines stimulate iNOS?
TNF, IFNγ
what do CD8+ T cells release?
Perforin and granzymes
what does CD40 bind to? where is CD40 located?
CD40 (on the APC) binds to CD40L aka CD154 (on the T cell)
what genes make up light chain variable regions?
heavy chain?
light chain = V, J
heavy chain = V, D, J
which complement pathway does factor H act on? which complements does it inactivate?
alternative pathway
inactivates C3b, alternative pathway C3 convertase
what is the function of C2b?
Kinin (increases vascular permeability)
what does LFA-1 bind to? on what cell is LFA-1 located?
LFA-1 binds to ICAM-1,2,3
LFA-1 is found on T-cells (also macrophages and neutrophils)
which antibody isotype is most efficient activator of complement?
IgM
what important cells have FcƐR? What is the result of IgE binding?
Mast cells, basophils, eosinophils; leads to degranulation
where is dimeric IgA present? where is the cleaved fragment?
dimeric IgA = lamina propria
cleaved fragment = lumen
what is the first antigen-associated step in B cell activation?
Antigen crosslinking with BCR
during which immunization are IgM levels higher than IgG? when does reverse occur?
primary immunization = high IgM
secondary immunization = high IgG
via what route do B cells enter lymph nodes? Memory B cells? Why are memory B cells different?
B-cells enter lymph nodes via HEV
Memory B cells enter via afferent lymphatic because they express little L-selectin
what complements make up classical pathway C3 convertase? Alternative?
classical C3 convertase = C4b2a
alternative C3 convertase = C3bBb
which regulator of terminal pathway is also known as protectin? what is another name for it?
CD59, MIRL (membrane inhibitor of reactive lysis)
which complement in the terminal pathway polymerizes to form membrane channel?
C9
what cells express CR1?
phagocytes, B-cells, RBC
what is the function of MCP-1? what is another name for MCP-1?
chemokine that recruits immune cells to site of injury
aka CCL-2
what antibody isotypes are present on immature B cells? Mature?
immature = IgM
mature = IgM and IgD
what cell is CD40 found on? CD40L? What is the role of CD40L?
CD40 found on B-cells (and other APCs)
CD40L found on T cells
CD40L helps in isotype switching
where is CD28 found? What is its function?
CD28 is found on T cells
Its function is co-stimulation to activate T cells
what cytokines inhibit Th1 subset?
what cytokines inhibit Th2 subset?
inhibit Th1 subset = IL-4, IL-10
inhibit Th2 subset = IFNγ
where is the B-cell when alternative splicing occurs?
bone marrow
what is the difference between a chemokine and chemoattractant?
chemokine is a special type of chemoattractant which has a disulfide bridge
what makes up the TCR complex?
TCR, CD3
which receptor do macrophages use for recognizing opsonin? which opsonin acts as signal?
CR1, C3b
which complements in the classic pathway are cleaved by C1?
C2, C4
what antibodies are expressed on the surface of plasma cells?
none
what do Th1 cells secrete?
IL-2, TNF, IFNγ
name the components of BCR
1 mIg (IgD or IgM), 2 CD79 a/b
which complement is associated with opsonization?
C3b
where is IgA distributed?
gut, intravascular, secretions
what function does CD2 have ini B-cell activation? What cell(s) has CD2 on its surface? What does CD2 bind to?
Adhesion between CD4+ T cell and B cell
CD2 is found on T cells and NK cells
CD2 (aka LFA-2) binds to LFA-3 (CD58)
what complements does DAF bind to? what convertases?
complements = C4b, C3b
convertases = classical + alt. pathway C3 convertase
