Brainscape's Knowledge GenomeTM

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


See full index

Imm 325 > C4 Phagocytes > Flashcards

C4 Phagocytes Flashcards

1
Q 
describe mast cells 
involved in 
released from what cell line then differentiate to what 
what is development influenced by 
what do they form
A

involved: allergy, asthma, hay fever. protective against bacteria & large pathogens: gut helminths
released from BM as CD24+, KIT+, CD13+ –> differentiate in tissue (skin, connective, epithelial)
form ETS: extracellular nets (made from DNA, histones, tryptase)

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

what happens upon activation of mast cell

A

become bigger & degranulates

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

what are mast cell deficient mice more susceptible to?

A

Bacterial infections
(C3b deficient mice also impaired mast cells)
(leukotriene KO mice more susceptible to bacterial infection)

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

what are the two types of rodent mast cells

A

Mucosal-type e.g. Gut mucosa - 40 day life span

Connective- tissue type - skin or peritoneal cavity >6 months

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

what are the types of human mast cells

What type of Th response favors production of mast cells

A

MCT: tryptase containing - mainly airway & small bowel submucosa
MCTC: tryptase & chymase - mainly skin & small bowel mucosa

Th2 –> IL4: promotes mast cell proliferation in presence of SCF
Th1 –> IFNy reduces mast cell number

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

role of SCF

A

stem cell factor: Acts to ↑ no. of mast cells present during an infection
(increases in intestine during bacterial infection)
Activity regulated by cytokines: IL-3, IL-4, IL-5, Il-9, IL10, GM-CSF receptors present

Th2 –> IL4: promotes mast cell proliferation in presence of SCF
Th1 –> IFNy reduces mast cell number

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

describe activation of mast cells

A
  1. Opsonized pathogens (antibodies: FceR1 for IgE & FcyR1 for IgG)
    (complement coated: CR3aR & C5aR)
  2. PRR (lectin binds mannosylated Mast cell R, TLR1-& & TLR9)
  3. Host molecules (fibrinogen/ fibronectin subfragments produced by cleavage of plasmin)
  4. Venom components
  5. Physical stimuli
  6. Chemical agents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe action of mast cells

A
  1. Secrete performed mediators (e.g. histmaine, mast cell proteases (25% content))
  2. Direct toxicity via granules produced: TNFa directly toxic to cells/pathogen
  3. Phagocytosis: produce respiratory burst - via MHCI (stim Tc)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Effectors of mast cells

A
  1. histamine (potent vasodilator/ facilitates arrival of inflammatory cells/antibodies to site of infection)
  2. LTB4 (chemotactic to neutrophils and eosinophils)
  3. Tryptase (can cleave C3 to C3a and activate fibroblasts)
  4. Tryptase & prostaglandin D2 (induces neutrophil influx )
  5. Prostaglandins (bronchoconstrictors/ cell permeability)
  6. Stimulate macrophages (via MIP1a & MIPB & MIP2)
  7. TNFa - major cytokine produced (upreg adhesion molecule/ increase bronchoresponsiveness)
  8. IL-4 (effects differentiation of Th –> Th2, stims IgE production)
  9. APC - via MHCI to stim Tc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe Eosinophils

A

Involved in protection against gut/lung infections
Phagocytic (not main job)
Can cause adverse effects e.g. Asthma
Can generate a respiratory burst (high levels of NAPDH oxidase)
Important in antigen presentation (have MHC-II molecules & co-stim molecules)
Make extracellular traps – explosive - mitochondial DNA

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

describe direct action of eosinophils & indirect action

A

Direct
Imp defense against gut helminths
Impt against viral infection e.g. Respiratory syncytial virus

Indirect
Tissue remodeling
Immunomulation
Defense against reinfection - memory development - present antigen

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

what is involved in the activation of eosinophils

A
  1. Opsonins: antibody – receptors for IgG (FcyRII) and IgA (FcyRI) and IgE (FcyRI, low)
    complement: receptors for C3a, C5a, CR1
  2. cytokines – receptors for IL-3, IL-5, GM-CSF
  3. chemokine receptors
  4. Toll receptors – express TLR1, TLR4, TLR7, TLR9 and TLR10 (TLR7 and TLR8 may be more impt).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

name the 4 types of eosinophils

A
  1. crystalloid granules: major basic protein, eosinophil peroxidase, eosinophil cationic protein, eosinophil neutrotoxin.
  2. Primary granules: Charco-t-Leyden crystal
  3. small granules
  4. secretory vesicles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe Cyrtalloid granules

A

all contents cytotoxic

  1. Eosinophil basic protein - causes degranulation of mast cells & basophils (toxic to parasites)
  2. Major basic protein - increases membrane permeability, effects lipid cell surface bilayer
  3. Eosinophil cationic protein - causes formation of selective ion pores
  4. Eosinophil derived neurotoxin - directly toxic
  5. Eosinophil peroxidase - involved in bacterial killing - catalyzes peroxidation of halides - formation of acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly

Imm 325 (18 decks)

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