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Host and Defense > Week 10 and 11 > Flashcards

Week 10 and 11 Flashcards

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1
Q

True or false… CD8 T cells have repeated activity until inhibited

A

True

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2
Q

True or false… some CD4 T cells have direct effector function and can kill

A

True

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3
Q

Which T cell kills virus-infected cells?

A

CD8 cytotoxic T cells

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4
Q

Which T cell activates infected macrophages and provides help to B cells for antibody production? They target microbes that persist in macrophage vesicles and extracellular bacteria

A

CD4 Th1 cells

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5
Q

Which T cells enhance neutrophil response and promote barrier integrity? They target klebsiella pneumoniae and fungi

A

CD4 Th17 cells

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6
Q

What T cells provide help to B cells for antibody production, especially isotype switching to IgE? They target helminths and parasites.

A

CD4 Th2 cells

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7
Q

Which T cells help B cells with isotype switching and antibody production?

A

TfH cells

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8
Q

Which T cells function to suppress other T cell responses?

A

Treg

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9
Q

True or false… CD8 T cells do not form memory cells

A

False, they do

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10
Q

___ are the most common T cell activator. They must be activated. Presentation occurs in the ___

A

Dendritic cells

Secondary lymphoid organs

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11
Q

How do dendritic cells uptake antigen? Describe their MHC expression and co-stimulation delivery.

A

Antigen uptake - macrophinocytosis and phagocytosis

MHC expression - low on immature dendritic cells, high on dendritic cells in lymphoid tissues

Co stimulation delivery - constitutive by mature, nonphagocytic lymphoid dendritic cells.

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12
Q

Dendritic cells mature through ______. Immature dendritic cells in the peripheral tissues encounter pathogens and are activated by ____. ___ signaling induces ___ and enhances processing of pathogen-derived antigens. ____ directs DC migration into lymphoid tissues and augments expression of co-stimulatory molecules and MHC molecules. The mature DC in T cell zone primes ____.

A

Antigen activation

PAMPS

TLR

CCR7

CCR7

Naive T cells

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13
Q

Antigen presenting cells distribute differently in lymph nodes. Describe where the different cells are found.

A

DCs - T cell areas

Macrophages - all areas

B cells - B cell areas

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14
Q

True or false… cross presentation of antigen via MHC 1 and MHC 2 is critical for CD8 T cell activation

A

True

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15
Q

Circulating naive T cells are exposed to antigen in _____. the naive T cells can get there by two routes. What are they?

A

Lymph nodes (they travel from node to node to survey lots of antigen)

Blood

Afferent lymph coming from an upstream lymph node

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16
Q

T cell activation requires three signals. What are they and what do they cause?

A

T cell receptor - activation

Co-stimulatory molecules - survival signal

Cytokines - differentiation, propagation

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17
Q

Co-stimulatory signals are required for T cell activation. ___ on APCs bind to ____ on T cells.

A

B7

CD28

(This gives a survival signal)

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18
Q

Which cytokine involved in T cell activation gives a propagation/clonal expansion signal?

A

IL-2

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19
Q

Naive T cell TCR activation in the absence of co-stimulation leads to ___

A

Anergy

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20
Q

Activation of T cells causes changes. Name 5 potential changes

A

Differentiation

Clonal expansion

Changes in surface protein expression

Migration to target tissues (lymph nodes or sites of infection/damage)

Effector functions

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21
Q

Resting T cells express a _____-affinity IL-2 receptor. Activated T cells express a ___-affinity IL-2 receptor. IL-2 signals in an ____ fashion.

A

Moderate

High

Autocrine

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22
Q

____ inhibits continued T cell activation and proliferation. Describe how. Why is this important?

A

CTLA-4

CTLA-4 (on T cell) binds B7 (on APC) more strongly than CD28. This will deliver inhibitory signals.

T cells dont die after their effector functions, thus must be inhibited. Binding an APC after activation will lead to inhibition.

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23
Q

What are the two ways naive CD8 T cells can be activated?

A

Dendritic cell sends strong enough signal to induce the CD8 T cell to produce IL-2, to cause it to proliferate and differentiate. Note that costimulatory receptors CD28 and B7 are necessary

Dendritic cells can activate CD4 T cells which will produce IL-2 to cause the CD8 T cell to become activated.

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24
Q

True or false… secondarysignals are necessary for CD8 T cell activation but not for active CD8 T cells to kill

A

True

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25
The only cells that kill via perforin and granzyme are ___ and ___ cells
NK CD8 T cells
26
Th1 cells are involved in ____ immunity whereas Th2 cells are involved in ___ immunity
Cellular Humoral
27
Differentiation of T helper cells involves what three things?
Cytokine induction Transcription factors Effector cytokines
28
What two cytokines induce differentiation into Th1 cells? What is the function of these cells?
IL-12 IFN-gamma Function: activate macrophages
29
What three cytokines induce differentiation into Th17 cells? What is the function of these cells?
IL-16 TGF-beta IL-23 Function: enhance neutrophil response
30
What cytokine induces differentiation into Th2 cells? What is the function of these cells?
IL-4 Activate cellular and antibody response to parasites
31
What two cytokines induce the differentiation into TFH cells? What are these cells' function?
IL-6 IL-21 Activate B cells. Maturation of antibody response.
32
What cytokine induces differentiation into Treg cells? What is a function of these cells?
TGF-beta Function: suppress other effector T cell function
33
Th1 cells activate macrophages. What do activated macrophages do? (4 things)
Express co-signaling ligands Kill intracellular pathogens Release cytokines and antimicrobial effectors Present antigen
34
____ T cells form granulomas when pathogen cannot be cleared? What are granulomas?
Th1 A compact aggregate of leukocytes that sequester pathogen. Involved in chronic inflammation, may be infectious or no infectious agents, several types of granulomas
35
True or false... pyrogenic granulomas are true granulomas
False
36
True or false... Th1 cytokines enhance the induced immune response to increase inflammation
True
37
How do Th2 cells promote tissue protection and repair?
Recruitment and activation of mast cells and eosinophils B cell activation (different than Th1) Cytokine release
38
True or false... TFH cells activate B cells and induce class switching
True
39
True or false... Treg cells suppresses other T cells, but must be interacting with the same APC in order to do so
True
40
What four things do Treg cells do?
Prevent T cell activation in the lymph node Stops adaptive immune response Prevents autoimmunity -TGF beta differentiation
41
Describe how Th17 and Treg cells regulate mucosal inflammation
Th17 is involved in tissue repairs, neutrophil recruitment, antimicrobial peptide production Treg cells inhibit mucosal inflammation Persistent Th17 function will result in autoimmunity
42
What is hypertrophy?
Increase in cell size | Atrophy - decrease in cell size
43
What is hyperplasia?
Increase in cell number
44
What is metaplasia?
Replacement of one type of cell with another type
45
What is dysplasia?
Disordered growth
46
Describe how hypertrophy in the heart can result in ischemia?
Blood vessels are more widely dispersed in the heart, limiting the dispersement of blood flow
47
Atrophy can be caused by...
``` Lack of hormonal signals Loss of innervation Lack of use Loss of blood supply Starvation Individual cell death ``` Note that dementia is atrophy in the brain
48
What is cachexia?
Fatty atrophy (Starvation) Fatal at 68% of normal body weight
49
Where is a common place where hyperplasia occurs?
Prostate (Also liver, kidney, breast, endometrium) Note that hyperplasia and hypertrophy often occurs together
50
Name three examples of metaplasia
Smoker's airways Cervix Barrett's esophagus
51
Define dysplasia
Disordered hyperplasia without maturation Preneoplastic
52
Name three examples of dysplasia
Uterine cervix Bowel in inflammatory bowel disease Esophagus with Barrett's
53
What types of cells are most prone to injury? Give examples
High metabolic activity (cardiac myocytes, renal tubular cells, hepatocytes) Rapidly proliferating (testicular germ cells, intestinal epithelium, hematopoietic cells)
54
What are the two degrees of cell injury? Define them and give some examples
Reversible - damage not enough to kill cell (toxic liver injury, severe exercise, hypoxia (loss of ATP), anaerobic glycolysis with lactate and acidosis) Irreversible - apoptosis or necrosis. More severe damage involving holes in membranes, long calcium influx, mitochondria loss
55
True or false... apoptosis is energy-requiring programmed cell death that usually only involves one cell at a time and does not involve inflammation
True
56
How does apoptosis work?
Caspase cascade is initiated because cytochrome C is released from mitochondria. Cytochrome C activates P53 which will then go to activate the caspase cascade.
57
What is the TdT stain used for?
Identifying DNA
58
True or false... apoptosis results in a shriveled cell with a pyknotic nucleus, with peripheral clumping of chromatin
True
59
What are the early events of necrosis?
Cell membrane disruption, calcium signal depletion, loss of ATP (loss of ions will cause cells to swell) Cell contents leak and cause acute inflammation.
60
What is gangrene?
Necrosis of whole anatomical areas
61
Describe the cellular changes in necrosis
Cytoplasm is deeper red (loss of mRNA). Cells swell. Nuclei not basophilic. Hemorrhage, acute inflammation, then chronic inflammation and fibrosis
62
What are the three different types of nuclear changes in cell death? Describe them
Nuclear pyknosis - shriveled and dark Karyolysis - digested, pale nucleus Karyorrhexis - nuclear fragmentation
63
Name 6 different patterns of necrosis. Describe them
Coagulative - with ischemia - makes infarct Liquefactive - loss of substance - in brain or lung abscess Fat necrosis - necrosis in fat Caseous necrosis - necrotizing granulomas - combination of liquefactive and coagulative fungal TB infection Gangrenous necrosis - necrosis of anatomic area Fibrinoid necrosis
64
Coagulative necrosis is common in the ___
Heart Forms a scar or thin area - leads to ventricular anuersym -note that in the last stage of coagulative necrosis, it is fibrous
65
Name some differences between necrosis and apoptosis
``` Necrosis: Injury-induced uncoordinated death Early cell membrane disruption Cell swelling Cells die in large groups Acute inflammation Always pathological ``` ``` Apoptosis: Programmed cell death Activation of caspases No swelling Usually one cell at a time No inflammation involved Can be a normal phenomenon ```
66
What are three brown storage products?
Lipofuscin - degraded lipid lysosomes. Bilirubin - hemoglobin breakdown product Hemosiderin - iron containing pigment
67
What is hemosiderin?
Hemochromatosis. Hereditary iron storage disease
68
What is anthracosis?
Carbon pigment Mostly in or near lungs (Coal worker's lung. "I have the black cough. *cough cough" - zoolander)
69
What is the role of macrophages, platelets, lymphocytes, and other blood cells in tissue healing?
Make proper cytokines to promote healing (TGF -beta) Matrix metalloproteinases Macrophages phagocytose and eliminate foreign material
70
What are the roles of fibroblasts in tissue healing?
Make collagen and rest of extracellular matrix Contractile myofibroblasts shrink wound
71
What are the roles of endothelial and epithelial cells in tissue healing?
Endothelial cells - make new blood vessels Epithelial cells - migrate and proliferate to cover wound or regenerate organ
72
What are the steps in tissue healing?
Inflammatory response and clot formation Fibroblasts, endothelial cells, and others migrate to clot and form granulation tissue and new epithelium Granulation tissue matures forming a scar with mature vessels and abundant collagen (10% strength at week 1) Scar matures - collagen remodeling and loss of excess blood vessels (occurs in months to years. ~80% of normal strength at 3 months
73
Repair after an inflammatory process may form a cavity in the ___ or in the ___. In other locations, it may form a scar because...
Brain Lung The damage is too severe for simple regeneration
74
Typically in tissue healing, ~____% of strength is achieved in the first week. After about three months ~___% of strength is achieved.
10 70-80
75
What happens if tissue repair is too much or too little?
Too much - hypertrophic scar formation, keloid formation (extends beyond site of injury), Desmond/fibromatosis ( a benign neoplasm) Too little - infection or mechanical stress
76
What are some things that can lead to too little tissue healing?
Steroids, poor perfusion, diabetes, malnutrition (especially vitamin C)
77
What are the three patterns of inflammation? Describe them.
Acute - begins almost immediatly, lasts minutes to days. Includes neutrophils, vessels, mast cells Chronic - begins at least 6 hours (to days) later. Includes lymphocytes, macrophages and plasma cells Granulomatous - variant of chronic inflammation. Aggregates of epithelium histiocytes/macrophages, giant cells, lymphocytes Note that mixes of all three of these can occur
78
What are the five clinical signs of inflammation?
``` Rubor - redness Tumor - swelling Calor - warmth Dolor - pain Loss of function ```
79
What causes the pain in inflammation?
PgE2 Bradykinin Substance p
80
What is exudate
Fluid coming from vessels into the site of inflammation. Fluid rich in protein (such as clotting factors, Ig, complement, etc.)
81
Which has a lower specific gravity, exudate or transudate?
Transudate (Lower specific gravity, protein, and LDH than exudate)
82
If you have leukocytosis with neutrophilia, what should you suspect?
Bacterial infection
83
If you have leukocytosis with lymphocytosis, what should you suspect?
Viral infection
84
If you have eosinophilia, what should you suspect?
Parasitic infection, autoimmune, or allergic Causes a type 2 response
85
How many mm of RBCs sink in one hour in a vertical capillary tube, normally?
less than 20mm
86
What are the laboratory signs of inflammation?
Increased sedimentation rate Because... Increased plasma fibrinogen, red cells clump and sink faster Fibrinogen is an acute phase reactant made in liver Nonspecific disease indicator Index of activty of a known disease
87
What are some other acute phase reactants? Describe them.
CRP - c reactive protein. Becomes abnormal faster than sedimentation rate. Can increase up to 1000 fold. Mild increases in otherwise healthy subjects indicate risk of atherosclerosis Procalcitonin - specific for bacterial infection. Can help determine if antibiotics are needed SAA (serum amyloid A protein) Ceruloplasmin (copper binding protein)
88
What are the cells involved in chronic inflammation?
Lymphocytes (sometimes plasma cells too) Macrophages Fibroblasts and new vessels in tissue repair
89
Giant cells are involved with...
TB granuloma
90
True or false... granulomas can calcify
True Calcification often develops in areas of necrosis
91
What is a type two immune response?
A response that involves Th2 lymphocytes, eosinophils, mast cells and basophils This is a reaction to parasites, allergies, and allergic-like diseases
92
True or false... basophils are the rarest type of blood cell. Like mast cells, they are coated with IgE, and are involved in allergies and responses to parasitic infection
True
93
Is appendicitis acute inflammation or chronic inflammation?
Acute
94
True or false... asthma is an allergic-like disease involving a type 2 response
True
95
What is the definition of SIRS in kids?
Core temp >38.5 or <36C Tachycardia (> 2 SD above normal for age) or bradycardia (<10th percentile for age) Mean respiratory rate > 2 SD above normal for age High or low WBC, or >10% immature neutrophils
96
How is T cell function different in infants?
Anti-inflammatory cytokine production diminished Less Immunoglobulin synthesis (B cells) Neutrophils differ from adult functional capacity
97
At what months of life are children at an increased risk for serious bacterial infection?
0-3 months
98
What is an SBI?
Serious bacterial infection Such as... Meningitis, bacteremia, UTI, pneumonia, osteomyelitis,
99
____ accounts for most of the SBIs infants within their first 3 months of life
UTIs
100
What are the three most common bacterial pathogens of neonatal SBI?
Group B streptococcus (S. Agalactiae) E. Coli (and other gram negative enteric bugs) Listeria monocytogenes
101
What are the most common viral causes of neonatal sepsis?
HSV 1 and 2 VZV Enteroviruses Influenza Adenoviruses RSV
102
True or false group B strep is alpha hemolytic and are common colonizers of the pharynx
False.. it is beta hemolytic and they are not common colonizers of pharynx (they colonize the GI and GU tracts)
103
What are some important virulence factors of group B strep?
Pilus-like structures Alpha C surface protein Beta-hemolysis/cytolysin Capsular polysaccharides
104
What are the clinical manifestations of GBS infection? What is the onset for early-onset, late-onset, late, late-onset?
Early-onset = <7days Late-onset = 7-89 days Late,late-onset = 90+ days
105
Early-onset GBS infection is commonly associated with maternal OB complications, and has the highest morality rate of 5-10%. What are some symptoms of this disease?
Respiratory distress, poor feeding, bradycardia, lethargy
106
What is the number one cause of early neonatal morbidity and mortality in the US?
GBS
107
Universal screening for GBS occurs in all pregnant women in __ - ___ weeks gestation using a vaginal-rectal specimen.
35-37
108
What is the drug of choice for treating neonatal GBS?
Penicillin
109
True or false... intrapartum antibiotic prophylaxis (IAP) only reduces early-onset GBS
True
110
True or false... listeria monocytogenes has incomplete beta-hemolysis, grows well at refrigerator temps, and has polar flagella, and is a gram positive rod
True
111
True or false... it is ok to narrow your antibiotics based on your gram stain
False
112
How is early-onset sepsis or late-onset meningitis acquired regarding listeria monocytogenes?
Early-onset: aquired in utero. Associated with prematurity Late-onset meningitis: onset about 2 weeks of age, acquired via birth canal
113
What is the drug of choice for treating neonatal listeria infection? Do cephalosporins work well?
Ampicillin (plus gentamicin) Cephalosporins dont have activity!!!
114
Think ____ with E.coli sepsis
Galactosemia
115
What is the best choice for empiric antimicrobial therapy for a febrile neonate?
Ampicillin, cefotoxamine, gentamycin Also note that you use acyclovir for HSV
116
What is the number one case of neonatal conjunctivitis?
Chemical irritation from silver nitrate
117
True or false... chlamydia trachomonas is the number one reportable STD in the US. 50% of infants are born to infected mothers. They will either develop conjunctivitis or pneumonia
True
118
What is the treatment give to prevent neonatal conjunctivitis?
Erythromycin (taken orally, not ocularly!!!)

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