2.5 Infection Process Flashcards
SA of mucosal tissues greater/less than that of skin
greater
Lymphatic vessels collect tissue fluid from. Fluid flows only toward
Loose CT
The heart
Function of lymphatic muscle tissue
Squeezes/pushes lymph in 1 direction
- b/c lymphatics have 1 way valves
3 ways to classify lymphoid tissue
- encapsulated organs
- Discrete lymphatic tissue
- diffuse lymphatic tissue
examples of encapsulated organs
Lymph nodes, thymus and spleen
Ratio of lymphatics to other cells is high/low for discrete lymphatic tissue/diffuse lymphatic tissue
High for discrete
Low for diffuse
Encapsulated organs have both __ lymphatic ___ and lymphatic ___
Diffuse
Tissue
Nodules
Primary lymphoid organs
thymus
BM
Secondary lymphoid organs
lymph nodes
spleen
MALT, GALT, BALT
diffuse lymphoid tissue examples
Urinary passages
reproductive tracts
Discrete lymphoid tissue examples
GALT (peyer’s patches and appendix)
BALT (tonsils)
Discrete lymphoid tissue structure is ___
permanent
Diffuse lymphoid tissue structure is ___
transient
What happens if mucosal surfaces dry out?
there’s no function
Describe mucins
- Long glycoproteins
- Secreted on mucosal membranes
- Allows liquids to remain inside and carries out agglutinated materials that then forms a clump in mucous that’s carried away w/ flow of material on mucosal surface
Tonsils and adenoids form a ring of lymphoid tissues called
Waldeyer’s ring
You find largest mucosal surface in
GI tract
Describe commensal. What are the 5 things it does?
- In GI tract
- assist the gut in digesting food and maintaining health
- synthesizes essential metabolites that we can’t
- break down plant fibers in food
- inactivate toxic substances in food or made by pathogens
- inhibits pathogens
- triggers immune response across epithelial border so you have an active immune response ready to go
M cells transport ___ and ___ from the gut lumen to ___
Microbes and antigens
Gut associated lymphoid tissue (to their antigens to DC and lymphocytes in peyer’s patch)
Steps for M cell to activated T cell
- M cells take up antigen by endocytosis and phagocytosis
- Antigen is transported across M cells in vesicles and released at basal surface
- Antigen is bound by DC, which activates T cells
DC can extend processes across the ___ to capture ___
Epithelial layer to capture antigen from intestinal lumen
Naive cells enter peyer’s patches via
HEV
Once B and T cells are stimulated in the peyer’s patch, they move to the ___, and then they’ll go to
mesentery lymph node
blood, heart, mucosal tissue
all cells found in mucosal surfaces are
effector lymphocytes (CD8, CD4, DC, plasma cell, mast cell, macrophage)
Steps for healthy tissue protected by mucosal immunity that’s infected by bacteria
- bacteria enter lamina propria by endocytosis and activate macrophage (NO INFLAMMATION)
- local effector cells respond, DC travel to mesentric lymph node to activate adaptive immunity
- effector B and T cells colonize
- infection’s terminated w/ minor tissue damage or no need to repair
is there inflammation on mucosal surfaces? why?
No b/c it’s a single epithelial layer and you don’t want to inhibit the function
What’s the cytokine along epithelium that’s produced by intestinal epithelium?
CCL25
___ interacts w/ CCL25 and brings T cells back to mucosal surface due to chemical gradient
CCR9
what are the 5 mechanisms of s-IgA
- binds and exports toxins and pathogens from lamina propria and secretes them out
- binds and neutralizes antigens in endosomes
- on the gut surface, it can bind and neutralize pathogens and toxins
- in the lumen, it can bind pathogen on M cell surface and take to lymphoid tissue
- picks up antigen in endosomes of M cell and takes it to lymphoid tissue (takes to DC for presentation)
Describe the subclasses of IgA
IgA1 - long fold region in antibody molecule
- produced in high amounts in areas where organism may produce IgA protease
IgA2 - short fold hinge that’s resistant to proteases
When your body can’t produce IgA, what takes over its function?
IgM
__ and ___ protects mucosal surface. This is ___ transport
IgM and IgA
Active transport
Transport of IgG from blood to lamina propria to gut lumen is all due to ___ receptor releasing IgG vesicle into lumen
FcRn
What proteins are similar to TLR? Where are they found? What do they bind? Function?
NOD1 and NOD2
Found in cytosol of enterocytes
Muramyl dipeptide
Binding of muramyl dipeptide stimulates NKkappa B to induce expression of cytokines which recruits neutrophils and monocytes
In worms you want a ___ response
adaptive
TH2 response against worms
- triggers cell response w/ eosinophils or mast cells
- produces IL-13 which induces epithelial cell repair and mucus
- IL-5 recruits and activates eosinophils
- drives B cells to produce IgE
- Drives mast cell recruitment via IL-3 and IL-9
- protective response
TH1 response against worms
- host damage
- activates macrophages
- produces IgG
- can stimulate an antibody dependent cytotoxic effect
anatomical features of mucosal immune system
- intimate interactions between mucosal epithelia and lymphoid tissues
- specialized antigen uptake by M cells
- discrete compartments of diffuse lymphoid tissues and more organized structures
effector mechanisms of mucosal immune system
- activated effector T cells predominate even in absence of infection
- plasma cells
immunoregulatory environment
- dominant and active downregulation of inflammatory immune response to food and other environmental antigens
- inflammation anergic macrophages and tolerance inducing DC
primary adaptive response produces __ effector cells and ___ memory cells. Can effector cells turn into memory cells?
More
Less
Yes
Do you go through somatic hypermutation and affinity maturation in IgG, IgM, or both?
IgG
Primary response produces ___ affinity IgM antibodies
Low
naive B cell binding to pathogen coated w/ specific antibody resutlts in
naive B cell isn’t activated
No production of low-affinity IgM antibodies
memory B cell binding to pathogen coated w/ specific antibody results in
Memory B cell activated
high affinity IgG, IgA, and IgE antibodies
First pregnancy of Rh- mother and Rh+ fetus result in
healthy baby
Second+ pregnancy of Rh- mother and Rh+ fetus results in
destruction of fetal erythrocytes
anemic newborn baby
First and subsequent pregnancies of Rh- mother and Rh+ fetus and infused anti-Rh IgG results in
anti-Rh IgG binds fetal erythrocytes and interacts w/ FcgammaR which inhibits primary immune response, so NO FETAL ERYTHROCYTES DESTROYED
healthy baby
T cells remain longer/shorter than antibody molecule
Longer
marker on naive CD4 T cell
CD45RA
Naive CD4 T cell and memory/effector CD4 T cell splicing
naive = CD45 exons are expressed
memory/effector = CD45 exons are spliced, so now it’s CD45RO
central memory cells express/lack CCR7 and remain in the ___
express
lymphoid tissue
Effector memory cells express/lack CCR7 and migrate to ___
lack
tissues
Effector T cells can become
quiescent memory cells or they die
gamma:delta T cells are located where? What are their steps activation?
gut epithelial layer
- infection of gut epithelial cell signals stress induced proteins
- bacteria go into gut and infected epithelial cell expresses MICs
- gamma:delta receptor and NK receptor NKG2D bind to MIC
- infected cell undergoes apoptosis and gamma:delta repairs wound
- dead cell’s replaced
What happens if NK cell detects normal MHC class I? What if there’s a presence of MIC?
negative signals sent to cell and nothing happens
Positive signals sent to cell and NK cell releases granules which kills cells in the area
