Immuno Q Bank Flashcards by Neil Mehta

under what conditions do T cells become anergic?

when it interacts with APC in absence of co-stimulatory interactions (CD28/B7)

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which CDs do double positive thymocytes contain?

CD2, CD3, CD4 and CD8

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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)

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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

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what complements make up classical pathway C5 convertase? Alternative convertase?

classical C5 convertase: C4b2a3b

alternative C5 convertase: C3b3bBb

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what are the constant regions associated with light chains?

kappa and lambda

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what heavy chain constant regions exist? what antibodies do they form?

delta = IgD

mu = IgM

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how many CD79a/b heterodimers are associated with a single mIg?

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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.

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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

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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

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what cells have FcγRI?

phagocytes; IgG binds to microbe, which then binds to FcγRI which signals the cell to perform phagocytosis

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what cell is the most efficient APC?

dendritic cell

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in which stage is CD20 expressed? CD19? CD40?

CD20 = Pre-B cell

CD19 = Pro-B cell

CD40 = naive/mature B-cells

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which 2 cells are fused to form hybridoma?

plasma cell and myeloma cell

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which antibody isotype has the highest serum concentration?

IgG

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what is another name for CD154? CD152?

CD154 = CD40L

CD152 = CTLA4

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what type of isotypes can be generated following switch recombination?

IgE, IgG, and IgA

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which antibody exists only in membrane bound form?

IgD

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what complement receptors do mast cells and basophils have?

CR3a/4a, CR5a

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which is the only antibody isotype not secreted by plasma cells?

IgD

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where in the body are B-cells located during VDJ recombination?

bone marrow

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which antibody isotypes are associated with J chain?

IgA (dimer) and IgM (pentamer)

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which isotype can cross the placenta?

IgG

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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?

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