Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HELENP CBG VIROLOGY AND IMMUNITY > CBG Lecture 28: Effector Mechanisms in the Immune System > Flashcards

CBG Lecture 28: Effector Mechanisms in the Immune System Flashcards

1
Q

name some infectious agents that insult the immune system - in size order, largest first

A

worms - protozoa (ameoba,leishmania,trypanosome) - fungi - bacteria -viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

name some infectious agents that insult the immune system - in size order, largest first

A

worms - protozoa (ameoba,leishmania,trypanosome) - fungi - bacteria -viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how do pathogens cause pathology

A

invasion
mutliplication
spread
production of diease - toxins, direct damage to host tissues,over reaction of IR - immunopathology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

name some modes of transmission of viruses

A

respiratory - adeno,paramyxo,rhino virus
faecal-oral - HepA
contact - herpes,papillo,HIV
arthropod/animal bite - flavivirus (yellow fever, dengue). Rhabdoviridae -rabies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the mode of transmission of a virus often determined by

A

stability of virus in enviro

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are effector mechanisms against viral infection

A

recognition of virus particules extracellularly followed by destruction and neutralisation
preventing viral replication within host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are viruses

A

obligate intracellular pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what ar eIR mechanisms

A

innate barriers and complement for membrane bound viruses
ABs
cytotoxic lymphocytes and NKs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

name an Ig thats made at mucosal surfaces

A

IgA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what region of AB varies between isotypes

A

Fc region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is MAC

A

initiated by antibodies due to complement activation

Membrane Attack Commplex damages viral envelope by perforin enzymes; forms pore, cause lysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe structure of naive T cells

A

scanty cytoplasm
small
resting cells with condensed chromatin
synthesze lttle RNa or protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is naive T cell proliferation and differentiation driven by

A

cytokine called IL-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what proteins are released by Cd8+ cells

A

perforin - deliver contents of granules into cytoplasm of target
2. granzymes - serine proteases- activate apoptosis
granulysis - antimicrobial actions, induce apoptosis
3. also release cytokines: IFN TNF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

in what fashion are effector molecules released from T cell granules

A

polar fashion as the specified recognition redistributes cytoskeleton and cytoplasmic components of the T cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why is the release of granules for CD8+ described as polar

A

because it redistributes the cytoskeleton and cytoplasmic components of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

whyich immmune response are NK cells part of

A

innate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how do some viruses try to avoid recognition by cytotoxic T cells

A

by downregulation of MHC - but

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what does perforin do

A

polymerizes to form pore in target membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what do granzymes do

A

serine proteases which activate apoptosis once in cytoplasm of target cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does IFN released by CD8 cells do

A

directly inhibits viral replication and induces the increase expression of MHC1 which increases chance infected cells will be recognised for cytotoxic attACK
activates macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

when is the humoral response initiated

A

when B cells that bind antigen are sinalled by heler T cells or by certain icrobial antigens alone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are the first ABs to be produced in a humoral response? why

A

IgM because IgM can be expressed without isotype switching

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

why do early IgM Abs tend to have low affinity

A

because they are produced before B cells have undergone somatic hypermutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

where do MHC class 1 molecules present antigens derived from

A

proteins in the cytosol - bound peptides transported by MHC1 to cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how do CD8+ cells kill

A

by releasing granszymes and perforin or by engagement of Fas on target cells by Fas ligand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

which chemical do CD8+ release to cause apoptosis

A

granzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what type of antigens to MHC class 2 present

A

antigens originating in intracellula vesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

which cells can T helper cells activate

A

macrophage and B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

name an innate lymphocyte

A

NK cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what activating receptors do NKs have - are they specific antigenic epitopes

A

MANY DIFFERENT - NOT SPECIFIC ANTIGENIC EPITOPES
antibody
viral glycoproteins
stress induced ligands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is the missing self hypothesis

A

when NKs detect a downregulation of MHCs - because viruses try to avid recognition by CTLs by downregulating MHC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what cells can NK cells kill - how quick

A

15mins

NK cells can kill virus infected or tumour cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is CD16

A

a low affinity IgG receptor - recognises complexed IgG antibodies
signals through association with Fc receptor common gamma chain
responsible for antibody-dependent cellular cytotoxicity (ADCC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what receptor on NK cell is responsible for ADCC antibody dependent cellular cytotoxicity

A

CD16 - low affinity IgG receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

outline process of ADCC

A

antibody dependent cellular cytotoxicity

  1. ab binds antigens on surface of target cells
  2. Fc CD16 receptors on NK cells recognise bound antibody
  3. cross linking of Fc receptors signals the NK cell to kill the target cell
  4. target cell died by apoptosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how is immunity to bacteria promoted

give examples of baxteria

A

TB, Salmonella

ABs and complement can act to kill bacteria directly and target them to phagocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what particles do phagocytes recognise

A

complement or antibody opsonised particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what are Fc receptors on phagocytes activated by

A

Abs bound to the surface of pathogens - enabling phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what are the main types of antibodies that phagocytes are activated by

A

IgG

41
Q

what does aggregation of immunoglobin on bacterial surface allow macrpohages to do

A

allows crosslinking of Fc receptors and therfore activation of macrophage leading to phagocytosis and destruction of bacterium

42
Q

how is a bound antibody distinguishioble from free immunoglobin

A

by its state of aggregation and the fact only aggregated bound immunoglobins can cross link Fc receptors

43
Q

what receptors are on macrophages that are specific for structures on pathogens

A

scavenger
mannose
LPS - lipopolysaccharide
PAMPs - pathogen associated molecular patterns

44
Q

what are phagolysosomes

A

fusion of phagosomes and lysosomes - where bacteria are attacked by enzymes and antimicrobial peptides

45
Q

name some enzymes present in phagolysosomes

A

proteases
elastase
lysozyme

46
Q

what is pH of phagolysosomes

A
47
Q

what is respiratory burst of phagolysosomes mediated by

A

NADPH oxidase

48
Q

outline steps of phagocytosis

A

1, bacteria attaches to membrane envaginations: pseudopodia

  1. bacterium ingested froming phagosome
  2. phagosome fuses with lysosome
  3. bacterium killed and digested by lysosomal enzymes
  4. digestion products are released from cell
49
Q

what are pseudopodia

A

membrane envaginations

50
Q

name some antimicrobial substances

A

peptides
interferons
granzymes
perforins

51
Q

how do pathogens cause pathology

A

invasion
mutliplication
spread
production of diease - toxins, direct damage to host tissues,over reaction of IR - immunopathology

52
Q

name some modes of transmission of viruses

A

respiratory - adeno,paramyxo,rhino virus
faecal-oral - HepA
contact - herpes,papillo,HIV
arthropod/animal bite - flavivirus (yellow fever, dengue). Rhabdoviridae -rabies

53
Q

what is the mode of transmission of a virus often determined by

A

stability of virus in enviro

54
Q

what are effector mechanisms against viral infection

A

recognition of virus particules extracellularly followed by destruction and neutralisation
preventing viral replication within host cell

55
Q

what are viruses

A

obligate intracellular pathogens

56
Q

what ar eIR mechanisms

A

innate barriers and complement for membrane bound viruses
ABs
cytotoxic lymphocytes and NKs

57
Q

name an Ig thats made at mucosal surfaces

A

IgA

58
Q

what region of AB varies between isotypes

A

Fc region

59
Q

what is MAC

A

initiated by antibodies due to complement activation

Membrane Attack Commplex damages viral envelope by perforin enzymes; forms pore, cause lysis

60
Q

describe structure of naive T cells

A

scanty cytoplasm
small
resting cells with condensed chromatin
synthesze lttle RNa or protein

61
Q

what is naive T cell proliferation and differentiation driven by

A

cytokine called IL-2

62
Q

what proteins are released by Cd8+ cells

A

perforin - deliver contents of granules into cytoplasm of target
2. granzymes - serine proteases- activate apoptosis
granulysis - antimicrobial actions, induce apoptosis
3. also release cytokines: IFN TNF

63
Q

in what fashion are effector molecules released from T cell granules

A

polar fashion as the specified recognition redistributes cytoskeleton and cytoplasmic components of the T cell

64
Q

why is the release of granules for CD8+ described as polar

A

because it redistributes the cytoskeleton and cytoplasmic components of the cell

65
Q

whyich immmune response are NK cells part of

A

innate

66
Q

how do some viruses try to avoid recognition by cytotoxic T cells

A

by downregulation of MHC - but

67
Q

what does perforin do

A

polymerizes to form pore in target membrane

68
Q

what do granzymes do

A

serine proteases which activate apoptosis once in cytoplasm of target cell

69
Q

what does IFN released by CD8 cells do

A

directly inhibits viral replication and induces the increase expression of MHC1 which increases chance infected cells will be recognised for cytotoxic attACK
activates macrophages

70
Q

when is the humoral response initiated

A

when B cells that bind antigen are sinalled by heler T cells or by certain icrobial antigens alone

71
Q

what are the first ABs to be produced in a humoral response? why

A

IgM because IgM can be expressed without isotype switching

72
Q

why do early IgM Abs tend to have low affinity

A

because they are produced before B cells have undergone somatic hypermutation

73
Q

where do MHC class 1 molecules present antigens derived from

A

proteins in the cytosol - bound peptides transported by MHC1 to cell surface

74
Q

how do CD8+ cells kill

A

by releasing granszymes and perforin or by engagement of Fas on target cells by Fas ligand

75
Q

which chemical do CD8+ release to cause apoptosis

A

granzymes

76
Q

what type of antigens to MHC class 2 present

A

antigens originating in intracellula vesicles

77
Q

which cells can T helper cells activate

A

macrophage and B cells

78
Q

name an innate lymphocyte

A

NK cell

79
Q

what activating receptors do NKs have - are they specific antigenic epitopes

A

MANY DIFFERENT - NOT SPECIFIC ANTIGENIC EPITOPES
antibody
viral glycoproteins
stress induced ligands

80
Q

what is the missing self hypothesis

A

when NKs detect a downregulation of MHCs - because viruses try to avid recognition by CTLs by downregulating MHC

81
Q

what cells can NK cells kill - how quick

A

15mins

NK cells can kill virus infected or tumour cells

82
Q

what is CD16

A

a low affinity IgG receptor - recognises complexed IgG antibodies
signals through association with Fc receptor common gamma chain
responsible for antibody-dependent cellular cytotoxicity (ADCC)

83
Q

what receptor on NK cell is responsible for ADCC antibody dependent cellular cytotoxicity

A

CD16 - low affinity IgG receptor

84
Q

outline process of ADCC

A

antibody dependent cellular cytotoxicity

  1. ab binds antigens on surface of target cells
  2. Fc CD16 receptors on NK cells recognise bound antibody
  3. cross linking of Fc receptors signals the NK cell to kill the target cell
  4. target cell died by apoptosis
85
Q

how is immunity to bacteria promoted

give examples of baxteria

A

TB, Salmonella

ABs and complement can act to kill bacteria directly and target them to phagocytes

86
Q

what particles do phagocytes recognise

A

complement or antibody opsonised particles

87
Q

what are Fc receptors on phagocytes activated by

A

Abs bound to the surface of pathogens - enabling phagocytosis

88
Q

what are the main types of antibodies that phagocytes are activated by

A

IgG

89
Q

what does aggregation of immunoglobin on bacterial surface allow macrpohages to do

A

allows crosslinking of Fc receptors and therfore activation of macrophage leading to phagocytosis and destruction of bacterium

90
Q

how is a bound antibody distinguishioble from free immunoglobin

A

by its state of aggregation and the fact only aggregated bound immunoglobins can cross link Fc receptors

91
Q

what receptors are on macrophages that are specific for structures on pathogens

A

scavenger
mannose
LPS - lipopolysaccharide
PAMPs - pathogen associated molecular patterns

92
Q

what are phagolysosomes

A

fusion of phagosomes and lysosomes - where bacteria are attacked by enzymes and antimicrobial peptides

93
Q

name some enzymes present in phagolysosomes

A

proteases
elastase
lysozyme

94
Q

what is pH of phagolysosomes

A
95
Q

what is respiratory burst of phagolysosomes mediated by

A

NADPH oxidase

96
Q

outline steps of phagocytosis

A

1, bacteria attaches to membrane envaginations: pseudopodia

  1. bacterium ingested froming phagosome
  2. phagosome fuses with lysosome
  3. bacterium killed and digested by lysosomal enzymes
  4. digestion products are released from cell
97
Q

what are pseudopodia

A

membrane envaginations

98
Q

name some antimicrobial substances

A

peptides
interferons
granzymes
perforins

HELENP CBG VIROLOGY AND IMMUNITY (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions