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Immunology PY2 > Lecture 26: Cutaneous & Mucosal-Associated Lymphoid Tissues > Flashcards

Lecture 26: Cutaneous & Mucosal-Associated Lymphoid Tissues Flashcards

1
Q

what are barrier immune tissues?

A

any tissues that separate our “insides” from the outside world

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2
Q

t/f there are some differences in barrier immune tissues, but the basic barriers are consistent

A

t

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3
Q

what are the 3 layered barriers?

A
  1. commensal microflora
  2. Epithelial & associated cells
  3. Sentinel Cells
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4
Q

what are the 3 functions of the commensal microflora?

A
  1. maintain balance
  2. help digestion
  3. crowd out pathogens
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5
Q

what is the function of epithelial and associated cells?

A

produce mucous or antimicrobial peptides/chemicals

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6
Q

what are the 3 functions of sentinel cells?

A
  1. tolerance to commensals
  2. first line of detection
  3. differ based on the location
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7
Q

commensal microfloral is also called ___

A

the microbiome

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8
Q

what is the commensal microbiome?

A

the friendly viruses, bacteria, fungi, protozoa and worms that exist in equilibrium and sometimes also symbiosis

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9
Q

commensal microflora is present at each barrier surface, but the ____ is different

A

composition

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10
Q

barriers and sentinel immune cells calibrate immunity at barriers by producing ____ and inducing ____

A

immune regulatory factors; regulatory immune populations

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11
Q

commensal entry is regulated by ___, ___, and ___ barriers

A

chemical, physical and cellular

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12
Q

In healthy barrier tissues, what immunologic features generate a tolerizing response?

A

TGFB, IL-10, Treg cells, and IgA-producing B cells

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13
Q

damage or invading stimulate innate & adaptive immune cells to generate ___ and ___ immune responses

A

Type 1 and Typ2

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14
Q

what are examples of innate immune cells?

A
  1. epithelial cells (enterocytes, goblet cells, paneth cells, M cells)
  2. macrophages, DCs (including pDCs) and innate lymphoid cells (ILCs)
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15
Q

what are some examples of adaptive immune cells?

A

B cells, T cells, NKT cells

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16
Q

barriers must simultaneously convey ___ and ___ to protect against dangerous invaders

A

regulation and immunity

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17
Q

t/f immune CONTEXT is important

A

t

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18
Q

local lymph nodes generate ____ responses to antigen from barrier tissues

A

systemic

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19
Q

____ and ___ direct activated lymphocytes to infected barrier tissues

A

adhesion molecules & chemokines

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20
Q

GALT contains well organized ____ and loosely organized ____

A

Peyer’s patches; isolated lymphoid follicles

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21
Q

in GALT, what are the major source of IgA-secreting B cells?

A

Peyer’s patches and isolated lymphoid follicles

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22
Q

____ lymphoid tissue broadly describes barrier organ-associate lymphoid tissues of the entire mucosal

A

mucosal associated lymphoid tissue (MALT)

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23
Q

B cells activated by T-dependent or T-independent antigens go on to differentiate into ____ and ____ cells

A

IgA synthesizing plasma cells; IgA-committed memory B cells

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24
Q

In T-independent activation of B cells, there is generally ____ (higher or lower) affinity and is dependent on ___ and ___

A

lower; BAFF and APRIL

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25
Q

innate lymphoid cells are lymphoid cells that mirror the functions of ___ cells

A

T cells

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26
Q

innate lymphoid cells reside in the ___ and are ____(fast or slow) acting

A

tissues; fast

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27
Q

what is the major role of innate lymphoid cells?

A

cytokine secretion

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28
Q

what are the 2 functions of mucous membranes?

A
  1. mechanical barrier of tight junctions btwn epithelial cells
  2. makes it difficult for pathogens to get in
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29
Q

the mucous in mucous membranes is secreted by ____ cells in the intestine, respiratory and GI tracts

A

goblet cells

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30
Q

what are 2 properties of the mucous secreted by mucous membrane?

A
  1. viscous fluid that traps and washes away potential pathogens
  2. contains antimicrobial substances like lysozymes
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31
Q

the lysozymes found in the mucous are made by ____ cells in the intestine

A

Paneth

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32
Q

some mucous membrane contain ___ cells that mechanically remove foreign substances (ex: lung muco-ciliary elevator)

A

ciliated

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33
Q

what is the function of enterocytes in mucosal immunity?

A

transport nutrients across the epithelial barrier and make cytokines in response to microbes that signal to immune cells

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34
Q

enterocytes realize there are pathogens bc the pathogens stimulate the ____

A

PRRs

35
Q

enterocytes signal to immune cells in the ____

A

lamina propria

36
Q

what 3 things does the intestinal microbiome provide?

A
  1. competitive protection
  2. metabolites from food
  3. help establish a balance btwn immune responsiveness & tolerance
37
Q

mucosa is in contact with ___

A

intestinal lumen

38
Q

what is the intestinal mucosa?

A

a single layer of epithelia cells and connective tissue

39
Q

the intestinal mucosa is also called the ___

A

lamina propria

40
Q

what is the site in teh intestinal mucosa with the most immune cell activity?

A

lamina propria

41
Q

what is the function of M (microfold cells)?

A

transport antigen from the lumen to DC

42
Q

where are M (microfold) cells located?

A

above Peyer’s patches and isolated lymphoid follicles

43
Q

M (microfold) cells transport antigens within ___ from teh luminal membrane to the ___ membrane

A

vesicles; pocket membrane

44
Q

what happens to the antigen-containign vesicles once microfold cells transport them to the pocket membrane?

A

vesicles fuse and deliver their contents to antigen-presenting cells

45
Q

t/f multiple mechanisms exist to transport antigen from the intestinal lumen to underlying antigen-presenting cells

A

t

46
Q

in addition to M cells, ____ cells transport small soluble antigens

A

goblet

47
Q

___ on epithelial cells allow for the transport of IgA-antigen complexes

A

Fc receptors

48
Q

some resident antigen-presenting cells directly sample the ____ contents

A

intestinal lumen

49
Q

Intraepithelial lymphocytes are called

A

IELs

50
Q

CD8+ T cells participate in ___ and ___

A

regulation and inflammation

51
Q

what are 3 ways in which CD8+ intraepithelial lymphocytes have less stringent requirements for activation?

A
  1. some TCR interact w/ microbial phospholipids w/o any need for MHC presentation
  2. some recognize stress-induced MCH-like molecules
  3. NKT cells are activated by glycolipid antigens presented by CD1 molecules
52
Q

cytokines secreted by activated intraepithelial lymphocytes shape the _____ immune response so that is the correct type to eliminate the invading pathogen

A

adaptive

53
Q

cytotoxic IELs kill what two types of cells?

A

cancerous and virus-infected

54
Q

lymphocytes that were initially activated in MALT recirculate in the ___ and preferentially home to ____

A

blood; mucosal tissues

55
Q

the homing of lymphocytes is mediated by ____ found in Peyer’s patches

A

vascular addressins such as MadCAM-1

56
Q

what is Mad-CAM-1?

A

mucosal addressin cell adhesion molecule-1

57
Q

what is the most abundantly produced Ig?

A

secretatory IgA

58
Q

what Ig is an important line of defense for mucosal surfaces against bacteria (ex: salmonella) and viruses (ex; polio)?

A

secretatory IgA

59
Q

what is a benefit of the polymeric structure of secretory IgA?

A

allows for the cross-linking of large antigens, making them easily trapped in mucus

60
Q

once IgA cross-links antigens and they are trapped in mucos, what happens to them?

A

antigens are eliminated by the action of cilia in the respiratory tract or perstalsis in the gut

61
Q

how does secretory IgA binding to bacteria & viruses affect infection?

A

prevents the receptor-mediated attachment to mucosal epithelial cells, which inhibits the infection & colonization by pathogens

62
Q

IgA from ___ cells is transported across the epithelial barrier

A

plasma

63
Q

the J-chain of dimeric IgA binds to a ____ receptor and this complex will cross to the lumen

A

poly-Ig

64
Q

what happens to the poly-Ig receptor to form the secretory component of secretory IgA/

A

the poly-Ig is cleaved by an enzyme

65
Q

what is a non-immune feature of the skin that acts as a barrier?

A

keratinocytes

66
Q

what are keratinocytes?

A

skin epithelial cells

67
Q

what are the functions of keratinocytes?

A

form a waterproof protective layer of keratin and secrete cytokines & antimicrobial factors

68
Q

what is an antimicrobial factor secreted by keratinocytes?

A

psoriasin

69
Q

the keratin layer is continuously replenished in what direction (from top down or from bottom up)?

A

from the bottom up

70
Q

____ secreted by sebaceous glands creates an acidic environment that inhibits microbial growth

A

sebum

71
Q

how does sweat have antibacterial activity?

A

contains lysozymes

72
Q

keratinocytes and skin mast cells express ____, resulting in proinflammatory and polarizing cytokine secretion in response to pathogens

A

PRRs

73
Q

what is the first immune defense in skin immunity?

A

intraepithelial lymphocytes

74
Q

what 2 cell types in the epidermis contribute to skin immunity?

A
  1. CD8+ Trm cells

2. y0 T cells with limited antigen receptor diversity

75
Q

what cells in the dermis contribute to skin immunity (2)

A
  1. CD4+ memory cells that circulate

2. y0 T cells that secrete IL-17 in response to IL-23 secreted by dermal APCs

76
Q

Y0 cells produce ___ in response to ___ release from dermal APcs

A

IL-17; IL-23

77
Q

unlike in mucosal tissues, the ____ does not have dedicated, organized lymphoid structures

A

skin

78
Q

what are langerhams cells in the skin?

A

specialized DCs in the skin

79
Q

what is the function of langerhans cells in the skin?

A

act as sentinels by extending processes between keratinocytes and transport antigen via lymphatic vessel to regional lymph nodes

80
Q

langerhans cells can assist in generating _____ or ____

A

tolerance or immunity

81
Q

t/f local skin responses can have systemic effects

A

t

82
Q

what is an example of local skin responses having a systemic effect?

A

vaccination

83
Q

T reg cells are plentiful in what parts of the skin?

A

dermis and epidermis

84
Q

T reg cells are mostly primed in what stage of life?

A

early

Immunology PY2 (20 decks)

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