B Cells Flashcards

1
Q

Fab region

A

the variable region and first constant region

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2
Q

Fc region

A

the bottom two constant regions

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3
Q

papain

A

will cleave antibody into monovalent parts –> 2 Fab regions and 1 Fc region

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4
Q

pepsin

A

will cleave antibody into bivalent Fab regions

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5
Q

monomeric antibodies

A

IgG, IgD, IgE

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6
Q

dimeric antibodies

A

IgA (4 antigen binding sites)

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7
Q

pentameric antibodies

A

IgM (10 antigen binding sites)

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8
Q

light chains contain _

A

variable region, junction region, and constant region

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9
Q

heavy chains contain _

A

variable region, junction region, constant region, and diversity region

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10
Q

How is secreted IgM generated?

A

alternative splicing of the transmembrane regions

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11
Q

IgM vs IgD

A

controlled by alternative splicing

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12
Q

IgM splicing

A

contains the mu constant region, the delta constant region is spliced out (mu = M)

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13
Q

IgD splicing

A

contains the delta constant region, the mu is spliced out (delta = D)

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14
Q

production of isotypes other than IgD

A

dependent on DNA recombination

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15
Q

What determines what isotype is made by B cells?

A

which cytokines are secreted by T cells

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16
Q

What cytokine stimulates IgE?

A

IL-4

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17
Q

two types of light chains

A

kappa and lambda

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18
Q

RAG1/2

A

binds recombination signal sequence to cause a hairpin loop to form, aligning the V RSS and J RSS

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19
Q

Ku70:Ku80

A

joins the DNA ends (V and J) where the RSS was cleaved

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20
Q

TdT

A

processes DNA ends and adds random nucleotides to achieve additional diversity

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21
Q

artermis:DNA-PK

A

opens DNA hairpins to generate palindromic sequences

22
Q

hyper-variable region is also known as _

A

complementarity determining (CDR) region

23
Q

Where are the CDR regions located?

A

on the variable regions of the antibody, each with 3

24
Q

CDR1 and CDR2 regions

A

encoded in the germline

25
Q

CDR3 regions

A

product of VDJ and VJ recombination

26
Q

antigen-independent diversity of antibodies

A

caused by recombination

27
Q

antigen-dependent diversity of antibodies

A

caused by somatic hypermutation after antigenic contact

28
Q

somatic hypermutation

A

causes changes in the CDR regions after antigen contact causing increased affinity

29
Q

antibody functions

A

neutralization of toxins, blocking virus entry, blocking bacteria binding, activation of classical pathway of complement, facilitating uptake by macrophages, working with complement, facilitate killing by NK cells, triggering degranulation of mast cells

30
Q

activation of classical pathway by IgM

A

IgM will bind to antigens on bacterial surface and adopt “staple” form –> C1q binds to bound IgM –> activation of C1r –> activates C1s protease

31
Q

activation of classical pathway by IgG

A

IgG molecules bind to antigens on bacterial surface –> C1q binds two IgG molecules –> activation of C1r –> activations of C1s protease

32
Q

antibody facilitation of macrophage uptake

A

free immunoglobulin will bind bacterial surface, allowing Fc region to bind FcR on macrophages

33
Q

antibody facilitation of NK cells

A

antibody binds antigens allowing the Fc receptors on NK cells to recognize the bound antibody –> signals NK cells to kill target cell

34
Q

antigen specificity determined by _

A

CDR 1,2,3 regions on variable regions

35
Q

function of antibody

A

determined by Fc portion of heavy chain

36
Q

pro-B cells

A

stage when D to J rearrangements are carried out

37
Q

pre-B cell receptor

A

composed of a mu-chain and a surrogate light chain and the signaling molecules Ig-alpha and Ig-beta

38
Q

pre-BCR signaling

A

halts heavy chain rearrangement and initiates light chain rearrangement

39
Q

immature B cells are all_

A

IgM

40
Q

central tolerance

A

induction of tolerance in primary lymphoid organs as a consequence of immature self–reactive lymphocytes recognizing self antigens

41
Q

peripheral tolerance

A

induction of unresponsiveness in peripheral sites as a result of self-reactive lymphocytes encountering self-antigens at the transitional B cell stage

42
Q

T cell independent antigen

A

have multiple repeating subunits recognized by B cells; polysaccharide antigens

43
Q

T cell dependent antigens

A

most common; full B cell response requires the participation of CD4 + T cells (CD40, CD40L)

44
Q

passive immunity

A

monoclonal antibodies, anecdotes, and maternal to fetus antibodies

45
Q

active immunity

A

natural infection, vaccines, toxoids

46
Q

production of monoclonal antibodies

A

take primed B cells after injecting mouse with antigen and fuse to myeloma cells –> expand hybridomas

47
Q

humanized monoclonal antibodies

A

fragment human variable region and insert mouse hybridoma CDR regions

48
Q

xenomouse

A

knockout heavy and light chain genes in embryo –> put in human heavy and light chain genes –> chimeric mouse will be born –> breed

49
Q

bi-specific antibodies

A

have two regions on antibody (i.e. anti-tumor and anti-hapten) –> anti-tumor will bind to tumor –> radiation can bind to anti-hapten –> radiation is concentrated

50
Q

magic bullets

A

adding a toxin to antibody constant region causes endocytosis of the antibody with toxin attached –> blocks translation