Ch 8 Flashcards Preview

Immunology > Ch 8 > Flashcards

Flashcards in Ch 8 Deck (69):
1

can be produced for an enormous variety of different specific antigens

antibodies

2

is determined before BCR and TCR encounter antigen

epitope specificity

3

highly variable in amino acid sequence

variable region

4

limited in variability for same Ig isotype

constant

5

heavy or light chain DNA gene segments rearranged

transcribed into RNA
translated into single heavy or light chain polypeptide

6

only what is used to construct the light chains and what is used to construct the heavy chains of the immunoglobulins synthesized by what

single chromosome
single different chromosome
single B cell or plasma cell

7

Each what has four light chain gene cluster

B cell and plasma cell

8

Each B cell and plasma cell has both what derived heavy chain gene clusters

maternally and paternally

9

ensures that each B cell and T cell synthesizes only one heavy and one light chain

allelic exclusion

10

allelic forms expressed in an individual

allotypes

11

in allelic exclusion: nonproductive arrangements lead to what

apoptosis during development

12

DNA breaks at

precise junctions of signal and coding sequences

13

VJ or VDJ unit can be translated in its entirety, yielding a complete antibody

productive

14

VJ or VDJ unit is likely to contain numerous stop codons, interrupting translation

nonproductive

15

Most DNA rearrangements involve

deletion and reannealing

16

some v segments notably what are in the opposite orientation

Kappa

17

Deletion does what to DNA

shortens

18

rearranges DNA but its length remains unchanged

inversion

19

B cells use groups of parts of genes to create different possible antibodies using what

recombination

20

adds or removes nucleotides to the exposed ends of the V, D, or J genes before they are reunited

terminal deoxylnucleotidyl transferase

21

terminal deoxylnucleotidyl transferase (TdT) modifies what

the length and coding sequences of the spliced genes

22

sites for intracellular signaling

ITAMs (Immunoreceptor tyrosine-based activation motifs)

23

What are the four regions of gene segments

variable
constant
diversity
joining

24

mediate genetic rearrangement and recombination

recombinases

25

lymphoid-specific complex of two proteins that catalyze DNA strand breakage and rejoin to form signal and coding joints

RAG-1/2

26

lymphoid-specific protein that adds N region nucleotides to the joints between gene segments in the Ig heavy chain and at all joints between TCR gene segments

TdT

27

stabilize binding of RAG 1/2 to recombination signal sequences, particularly to the 23-bp RSS; stabilize bend introduced into the 23-bp spacer DNA by the RAG 1/2 proteins

HMG 1/2 proteins

28

binds DNA coding and signal ends and holds them in protein-DNA complex

Ku70 and Ku80 heterodimers

29

in complex with Ku proteins, recruits and phosphorylates Artemis

DNA PKcs

30

opens the coding end hairpins

Artemis

31

stabilizes and activates DNA ligase IV

XRCC4

32

in complex with XRCC4 and Cernunnos ligates DNA ends

DNA ligase IV

33

with XRCC4, activates DNA ligase IV

Cernunnos

34

diversity in variable region

allelic exclusion

35

occurs prior to encounter with antigen

allelic exclusion

36

produces Ig of only on specificity and one isotype

B cell

37

express IgM and IgD antibodies

Mature B cells

38

control whether the cell produces membrane-bound or secreted IgM

mRNA splicing mechanisms

39

Ig proteins consist of what three things

two identical heavy chains
two identical light chains
each set of gene families are encoded on separate chromosomes

40

Chain genes include V, J, and C segments

kappa light chain

41

chain genes pair each J segment with a particular C segment

Lambda light chain

42

uniting variable and constant regions occur at

mRNA level

43

Six steps of the kappa and lambda light chains

nuclear DNA
DNA between a V gene and a J gene is deleted
the exposed V and J genes are joined together
mRNA is transcribed to include the rearranged VJ genes and the C gene
The intervening mRNA is deleted to bring the VJ genes together with the C gene
mRNA is transcribed into protein

44

single cluster of genes and contain a single variable and 3-4 constant

heavy chains

45

deletion of heavy chain does what

united random D to J

46

second deletion of heavy chains does what

unites random V to DJ

47

eight steps for the heavy chain

nuclear DNA
DNA between a D gene and a J gene is deleted
Exposed D gene and J genes are joined together
DNA between a DJ and a V gene is deleted
Exposed DJ and V genes are joined together
mRNA is transcribed from VDJ through the C gene
mRNA is spliced to place VDJ adjacent to either the C mu or the C delta gene
mRNA is translated into protein to produce either the IgM heavy chain or the IgD heavy chain

48

of gene segments produces diversity in the antigen-binding sites of immunoglobulins

random recombination

49

which variable region genes rearrange first and second

heavy chain
light chain

50

is determining by the combination of heavy and light chain variable regions

epitope binding

51

epitope binding does what to the number of epitopes that may be recognized

greatly increases

52

displays monomeric IgM and IgD on cell surface

unstimulated B cell

53

when stimulated, B cells may do what

change isotype, but not epitope specificity

54

influences humoral immunity

isotype switch

55

what determines function

isotype

56

permits adaptive immunity to produce antibodies with identical specificities that can mount different immune responses

isotype switch

57

what occurs only during an active immune response

isotype switch

58

regulated by cytokines secreted by antigen-activated T cells

isotype switch

59

stimulated B cells that synthesize and secrete antibodies

plasma cells

60

stimulated B cells that are held in reserve against future antigen exposure

memory B cells

61

when restimulated, undergo further DNA rearrangement to class switch

memory B cells

62

isotype switch does not occur in what cells

T

63

rearrangements to produce particular isotypes may occur directly through the excision of larger DNA segments or what

in stages during multiple rounds of memory B cell activation involving the deletion of smaller DNA segments

64

The humoral immune response is diversified by

producing multiple isotypes with the same antigen binding specificity

65

subsequent antigen exposure, class switching, and point mutations to variable light and variable heavy chains

somatic hypermutation

66

fine-tunes antibodies response to frequent antigens, affinity maturation, and rapid proliferation follows restimulation

somatic hypermutation

67

somatic hypermutation occurs only in what cells

B

68

occurs when memory B cells are reactivated and undergo proliferation

DNA replication

69

as what accumulates in the genes contributing to the epitope binding regions of the encoded immunoglobulins

mutations