Ch 10 Flashcards Preview

Immunology > Ch 10 > Flashcards

Flashcards in Ch 10 Deck (128):
1

gatekeeper for adaptive immune responses

innate immune system

2

initially develop slowly

adaptive response

3

ingested proteins are enzymatically digested

antigen presentation

4

in antigen presentation some peptide fragments are loaded into which MHC class molecules

I and II

5

allelic forms of MHC genes are linked

haplotypes

6

each individual inherits how many haplotypes from each parent

one

7

MHC alleles are expressed

codominantly

8

both maternal and paternal MHC genes are expressed from in offspring cells

codominance

9

what makes transplantation difficult

heterozygous at each locus

10

MHC Class I presents

intracellular antigen peptides

11

MHC Class II presents

extracellular antigen peptides

12

self proteins
viral infections
abnormal cells

MHC Class I

13

provides a way for checking that cells are self and are generally healthy

self proteins

14

more restricted; generally found on cells involved in immune responses
helps to direct responses against threats-things that shouldn't be in our systems

MHC Class II

15

located at potential microbial portals of entry or serve as sentinels

dendritic cells

16

engagement of cell surface receptors associated with clathrin-coated pits

phagocytosis

17

doesn't require clathrin

macropinocytosis

18

decrease phagocytic activity; increase MHC Class II synthetic activity

mature dendritic cells

19

direct sensing through PRRs that recognize PAMPs
indirect sensing by other receptors (complement)
direct threat sends to lymph nodes

immature dendritic cells

20

what type of dendritic cells play a huge role in phagocytosis

immature

21

most self-reactive CD4+ cells are removed during

thymic selection

22

nucleated cells degrade and recycle cytoplasmic proteins
intracellular microbes and viruses bind to cell membrane and directly enter cytoplasm
tagged with ubiquitin
degraded by proteasome
peptides transported to ER by TAP-1 and TAP-2
move to golgi

MHC Class 1

23

recognition by CD8+ T cells
transport to cell surface

golgi

24

allows peptides to load into MHC Class I

peptides transported to ER by TAP-1 and TAP-2

25

traffics from endoplasmic reticulum to Golgi and is budded off in vesicle

pMHC I

26

largely direct adaptive response

T cell activation

27

restricted to recognizing peptides presented in the context of self MHC alleles

T cells

28

can only recognize peptides presented by MHC Class I/II

CD8+/CD4+ T cells

29

can't be recognized by T cells

whole antigens

30

only processed what can be recognized by T cells

antigen peptide fragments

31

initiated by TCR recognition of pMHC

immunologic synapse

32

interaction stabilized by CD4 or CD8 binding to non-peptide

immunologic synapse

33

pMHC: TCR: CD complex through association of CD3 complex

first signal directing T cell activation

34

costimulatory group of signals

second signal directing T cell activation

35

without costimulation there is what

anergy
apoptosis

36

selectively unresponsive

anergy

37

go on to become cytotoxic T cells

CD8+ T cells

38

differentiate into different subsets

CD4+ T cells

39

facilitate activation

positive costimulatory receptors

40

positive costimulatory receptors have

CD28
ICOS

41

help turn activation off

negative costimulatory receptors

42

negative costimulatory receptors have

CTLA-4
PD-1
BTLA

43

expressed by B cells, some antigen presenting cells and T cells

ICOS

44

expressed by professional antigen presenting cells and medullary thymic epithelium

CD28
CTLA-4

45

activation of naïve T cells

CD28

46

maintenance of activity of differentiated T cells; a feature of T and B cell interactions

ICOS

47

expressed by professional antigen presenting cells. some T and B cells, and tumor cells

PD-1

48

expressed by some antigen presenting cells, T and B cells

BTLA

49

negative regulation of the immune response (maintaining peripheral T cell tolerance; reducing inflammation; contracting T cell pool after infection is cleared)

CTLA-4

50

negative regulation of the immune response, regulation of Treg differentiation

PD-1
BTLA

51

results if a costimulatory signal is absent

clonal anergy

52

if only signal 1 is received in clonal anergy what happens to the cell

cell is rendered nonresponsive

53

clonal anergy help provides what

tolerance

54

stabilized T cell antigen presenting cell and promotes migration of adhesion molecules with T cell membrane

immunologic synapse

55

initiate signaling cascade

ITAMs

56

ITAMs are found on what complex

CD3

57

what engages pMHC Class II

TCR

58

engages pMHC II to activate LCK

CD4

59

phosphorylates ITAMs to activate ZAP-70

LCK

60

phosphorylates LAT and activates PLC-gamma

ZAP-70

61

cleaves PIP2 to form DAG and IP3

PLC-gamma

62

this plus calcium activates PKC and IP3 + Ca2+ activates calcineurin

DAG

63

phosphorylates I kappa B causing NF kappa B to migrate to the nucleus.

PKC

64

activates ras and rac

LAT

65

initiate phosphorylation cascades to activate AP-1 family transcription factors

ras and rac

66

effector T helper subsets are distinguished by three properties

distinct polarizing cytokine set that induces expression of:
a master gene regulator that regulates expression of:
a signature set of effector cytokines produced by that subset

67

initial encounter of T cells with antigen

priming

68

what is important for development

priming

69

pathway uncommitted
nature of signal determines outcome

Th0 cells

70

secrete IL-2, IFN-gamma, and TNF-beta
responsible for cell-mediated functions
CTL activation and macrophages

Th1 cells

71

secrete IL-4, IL-5, IL-6, IL-9, IL-10, and IL-13
regulates B cell activity and differentiation

Th2 cells

72

stimulated to secrete various cytokines and express cell-surface cytokine receptors

CD4+ T cell

73

characterized by strong IFN-gamma production

Th1 cells

74

leads to class switching to IgG classes that support phagocytosis and complement fixation
supports differentiation of antiviral CD8+ killer T cells

strong IFN-gamma production

75

what induces Th1 differentiation

IL-12, IL-18 and IFN gamma

76

what promotes Th2 subset differentiation

IL-4

77

acts to promote activities of eosinophils against helminths

IL-4

78

induces class switching to IgE, which helps other cell types to release anti-parasite inflammatory mediator molecules

IL-4

79

can also induce class switching

IL-5

80

overlaps with IL-4

IL-13

81

interaction increases CD80/86 expression

antigen presenting cells-CD4+

82

recognition of pMHC class I causes expression of IL-2 receptors

CD8+ T cell

83

differentiate into cytotoxic T cells

CD8+ t cell

84

contain granules that contain perforin, acytolytic protein, and granzyme to induce apoptosis of target cell

CD8+ t cell

85

CD45 may also change isoform
decrease surface expression of CD62L
increase expression of some adhesion molecules
express CD28

memory T cell

86

memory t cells express CD28 and are more likely to what

rapidly respond to CD80/86 on antigen presenting cells

87

memory t cells increase expression of some adhesion molecules does what

direct towards sites of inflammation

88

memory t cells decrease surface expression of CD62L doesn't direct toward what

lymph nodes

89

what cells express TCR and CD28

naïve CD4+ t cells

90

engagement inactivates the CD4+ t cells

CD152:CD66

91

activated CD4+ t cells express

CD28 and CD152

92

antigen presenting cells express pMHC Class II and what

CD80 and/or CD86

93

first signal

TCR
pMHC II

94

costimulation

CD28
CD80
CD86

95

are a special class of t cell activators

superantigens

96

effectively short circuits need for costimulation
produces dramatic cytokine

superantigens

97

viral/bacterial proteins that bind to specific V beta regions of TCRs and alpha chain of class II MHC molecules

superatigens

98

clonal selection hypothesis basics

each B cell bears a single type of Ig receptor
on stimulation, each cell will create a clone of cells bearing the same Ag receptor as the original

99

recognize and bind epitopes on either cell-bound or soluble molecules

BCRs

100

associated with Ig alpha/Ig beta and contains ITAMs

BCR

101

induces tyrosine kinases

crosslinking

102

antigen must have multiple what

epitopes

103

engages epitopes

BCR

104

sites for intracellular signaling

ITAMs

105

phosphorylates and activates PLC-gamma

syk

106

phosphorylate ITAMs on Ig alpha and Ig beta to activate syk

lyn, lck, blk, fyn

107

cleaves PIP2 to form,DAG + IP3

PLC gamma

108

responses require help from t cells

t dependent

109

mediated by b-2 b cells binding to antigens
are typically generated upon recognition of protein Ag

t dependent

110

responses do not require t cell help

t independent

111

generated upon exposure to multivalent/polymerized Ag
mediated by B1 cells

T independent

112

bind to b cells through PRRs and mIgs

T1-1 Ag

113

cross-link large numbers of BCRs

TI-2 Ag

114

polyclonal activators, bind to surface structures

TI-1 antigens

115

activate irrespective of BCR epitope specificity
typically microbial
stimulate both immature and mature b cells

TI-1 antigens

116

contain repetitive epitopes, often multivalent polysaccharides

TI-2 antigens

117

specificity activate only mature b cells

TI-2 antigens

118

in T dependent activation a second signal is often provided by

CD4+ t cells

119

presentation of pMHC class II by b cel or antigen presenting cells

immunologic response

120

leads to expression of IL-4R
when encounters IL-4, proliferation and differentiation into antibody-secreting plasma cells

costimulation

121

humoral response to TI is different than TD 3 reasons

response to TI antigens is generally weaker
no memory cells are formed with TI
IgM is predominant antibody secreted

122

terminally differentiated b cells

plasma cells

123

actively secrete immunoglobulins
short-lived, active in fighting infection
not all b cells become this

plasma cells

124

poised for reencounter with same epitope

memory cells

125

membrane-bound immunoglobulins
long-lived remembers encountered antigens
can be converted to plasma cells

memory cells

126

antigen recognized by b cells and antigen-presenting cells display peptides to

CD4+ t cells

127

are activated and await a help signal from

CD4+ t cells

128

help signals cause b cells to proliferate and differentiate

t cell