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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
innate lymphoid cells are lymphoid cells that mirror the functions of ___ cells
T cells
26
innate lymphoid cells reside in the ___ and are ____(fast or slow) acting
tissues; fast
27
what is the major role of innate lymphoid cells?
cytokine secretion
28
what are the 2 functions of mucous membranes?
1. mechanical barrier of tight junctions btwn epithelial cells 2. makes it difficult for pathogens to get in
29
the mucous in mucous membranes is secreted by ____ cells in the intestine, respiratory and GI tracts
goblet cells
30
what are 2 properties of the mucous secreted by mucous membrane?
1. viscous fluid that traps and washes away potential pathogens 2. contains antimicrobial substances like lysozymes
31
the lysozymes found in the mucous are made by ____ cells in the intestine
Paneth
32
some mucous membrane contain ___ cells that mechanically remove foreign substances (ex: lung muco-ciliary elevator)
ciliated
33
what is the function of enterocytes in mucosal immunity?
transport nutrients across the epithelial barrier and make cytokines in response to microbes that signal to immune cells
34
enterocytes realize there are pathogens bc the pathogens stimulate the ____
PRRs
35
enterocytes signal to immune cells in the ____
lamina propria
36
what 3 things does the intestinal microbiome provide?
1. competitive protection 2. metabolites from food 3. help establish a balance btwn immune responsiveness & tolerance
37
mucosa is in contact with ___
intestinal lumen
38
what is the intestinal mucosa?
a single layer of epithelia cells and connective tissue
39
the intestinal mucosa is also called the ___
lamina propria
40
what is the site in teh intestinal mucosa with the most immune cell activity?
lamina propria
41
what is the function of M (microfold cells)?
transport antigen from the lumen to DC
42
where are M (microfold) cells located?
above Peyer's patches and isolated lymphoid follicles
43
M (microfold) cells transport antigens within ___ from teh luminal membrane to the ___ membrane
vesicles; pocket membrane
44
what happens to the antigen-containign vesicles once microfold cells transport them to the pocket membrane?
vesicles fuse and deliver their contents to antigen-presenting cells
45
t/f multiple mechanisms exist to transport antigen from the intestinal lumen to underlying antigen-presenting cells
t
46
in addition to M cells, ____ cells transport small soluble antigens
goblet
47
___ on epithelial cells allow for the transport of IgA-antigen complexes
Fc receptors
48
some resident antigen-presenting cells directly sample the ____ contents
intestinal lumen
49
Intraepithelial lymphocytes are called
IELs
50
CD8+ T cells participate in ___ and ___
regulation and inflammation
51
what are 3 ways in which CD8+ intraepithelial lymphocytes have less stringent requirements for activation?
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
cytokines secreted by activated intraepithelial lymphocytes shape the _____ immune response so that is the correct type to eliminate the invading pathogen
adaptive
53
cytotoxic IELs kill what two types of cells?
cancerous and virus-infected
54
lymphocytes that were initially activated in MALT recirculate in the ___ and preferentially home to ____
blood; mucosal tissues
55
the homing of lymphocytes is mediated by ____ found in Peyer's patches
vascular addressins such as MadCAM-1
56
what is Mad-CAM-1?
mucosal addressin cell adhesion molecule-1
57
what is the most abundantly produced Ig?
secretatory IgA
58
what Ig is an important line of defense for mucosal surfaces against bacteria (ex: salmonella) and viruses (ex; polio)?
secretatory IgA
59
what is a benefit of the polymeric structure of secretory IgA?
allows for the cross-linking of large antigens, making them easily trapped in mucus
60
once IgA cross-links antigens and they are trapped in mucos, what happens to them?
antigens are eliminated by the action of cilia in the respiratory tract or perstalsis in the gut
61
how does secretory IgA binding to bacteria & viruses affect infection?
prevents the receptor-mediated attachment to mucosal epithelial cells, which inhibits the infection & colonization by pathogens
62
IgA from ___ cells is transported across the epithelial barrier
plasma
63
the J-chain of dimeric IgA binds to a ____ receptor and this complex will cross to the lumen
poly-Ig
64
what happens to the poly-Ig receptor to form the secretory component of secretory IgA/
the poly-Ig is cleaved by an enzyme
65
what is a non-immune feature of the skin that acts as a barrier?
keratinocytes
66
what are keratinocytes?
skin epithelial cells
67
what are the functions of keratinocytes?
form a waterproof protective layer of keratin and secrete cytokines & antimicrobial factors
68
what is an antimicrobial factor secreted by keratinocytes?
psoriasin
69
the keratin layer is continuously replenished in what direction (from top down or from bottom up)?
from the bottom up
70
____ secreted by sebaceous glands creates an acidic environment that inhibits microbial growth
sebum
71
how does sweat have antibacterial activity?
contains lysozymes
72
keratinocytes and skin mast cells express ____, resulting in proinflammatory and polarizing cytokine secretion in response to pathogens
PRRs
73
what is the first immune defense in skin immunity?
intraepithelial lymphocytes
74
what 2 cell types in the epidermis contribute to skin immunity?
1. CD8+ Trm cells | 2. y0 T cells with limited antigen receptor diversity
75
what cells in the dermis contribute to skin immunity (2)
1. CD4+ memory cells that circulate | 2. y0 T cells that secrete IL-17 in response to IL-23 secreted by dermal APCs
76
Y0 cells produce ___ in response to ___ release from dermal APcs
IL-17; IL-23
77
unlike in mucosal tissues, the ____ does not have dedicated, organized lymphoid structures
skin
78
what are langerhams cells in the skin?
specialized DCs in the skin
79
what is the function of langerhans cells in the skin?
act as sentinels by extending processes between keratinocytes and transport antigen via lymphatic vessel to regional lymph nodes
80
langerhans cells can assist in generating _____ or ____
tolerance or immunity
81
t/f local skin responses can have systemic effects
t
82
what is an example of local skin responses having a systemic effect?
vaccination
83
T reg cells are plentiful in what parts of the skin?
dermis and epidermis
84
T reg cells are mostly primed in what stage of life?
early

Immunology PY2 (20 decks)

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