Brainscape's Knowledge GenomeTM

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


See full index

MIMM 214 > Innate immunity: Basics and Phagocytosis > Flashcards

Innate immunity: Basics and Phagocytosis Flashcards

1
Q

How do pathogens enter

A

Mucosal and epithelial - skin - surfaces
External barrier

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

How can pathogen cause infection

A

Pathogen must enter the body - breach one of these barriers
Diff routes of entry
- ex = airborne microorganisms enter through lining of respiratory tract

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

Why is human skin resistant to colonization by E. coli despite exposure to it

A

Physical barriers = also chemical barrier
Skin has barrier against it

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

Describe epithelial surfaces

A

Provide first barrier against infection = skin, gut lining epithelium, respiratory epithelium, mucosal membranes
Epithelial cells have prrs that bind pamps

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

What provides innate immunity

A

Saliva
Hair
Mucus
Tears

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

What do epithelial layers produce

A

Protective substances = acidic ph, antimicrobial peptides (defensins)

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

Name cellular elements of innate immunity

A

Neutrophils (main) and other granulocytes
Monocytes and macrophages
Dendritic cells
Nk cells and other innate lymphoid cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe monocytes and macrophages

A

Macrophages = mostly tissue resident
Tissue specific variants = kupffer cells, microglia (macrophages of cns) , intraglomerular mesangial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Name types of dendritic cells = 3

A

Immature

Mature =
conventional
Plasmacytoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name some key molecules innate immunity

A

Antimicrobial enzymes
Antimicrobial peptide s
Complement

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

Give ex of anti microbial enzyme

A

Lysozyme= digest peptidoglycan (cell wall gram pos bacteria)

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

Give ex of anti microbial peptides

A

Defensins —> disrupt cell membrane (creates pore)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe stages of infection and response to it

A

Pathogens adhere to epithelium
Immune cells activated = local infection, penetration of epithelium
Local infection of tissues
Adaptive immunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is definition phagocytosis

A

Engulfment and internalization of pathogens or their comments upon binding to receptors on cell surface of phagocytes = have to be prompted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name phagocytes that mediate phagocytosis

A

Macrophages
Granulocytes:neutrophils
Dendritic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What can phagocytosis lead to

A

Removal and killing of pathogens
Clearing debris= prrs recognize damps (released when cells near during, damage associated molecular patterns)
Generation of peptides for presentation to t cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe macrophage as phagocyte

A

Also dendritic cells can do phagocytosis and process antigen
Macrophages = presenting peptide antigen to T cell on mhc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe receptors involved in phagocytosis

A

Many are prrs
Not all prrs induce phagocytosis - but many do

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe indirect phagocytosis

A

Phagocyte recognition of soluble proteins that are bound to microbial surfaces (opsonins, bind to surface of microbe ) = aka soluble pattern recognition proteins —> enhance phagocytosis (opsonization)
Ex = antibodies and complement proteins, phagocytic cells have receptors for opsonins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe phagocytosis - initial

A

Initiated when receptors interact with ligand/pathogen
Bacterium binds to prrs (pamp binds)
Prompts membrane protrusions that extend = pseudopodia —> leads to engulfment bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe phagocytosis - internalized

A

Pathogen internalized in large membrane enclose endocytic vesicle = phagosome (goes into vesicle)

22
Q

Describe phagocytosis - fusing

A

Phagosome fuses with one or more lysosomes —> phagolysosome = lysosomal contents released

23
Q

Describe phagocytosis - kill

A

Ph drops and killed
Phagolysosome acidity’s = acquires antimicrobial peptides and enzymes to kill pathogen
Activated enzymes at low ph and chops up bacteria

24
Q

Describe neutrophils - phagocytosis

A

Contain dif types of cytoplasmic granules = primary granules and secondary granules

25
Q

What do granules of neutrophils do

A

Fuse with phagosome (phagolysosome) and release additional enzymes and antimicrobial peptides that attack the microorganism

26
Q

How are neutrophils diff from other cells

A

Macrophages and dendritic cells do not have granules

27
Q

What happens when Ligand binding/phagocytosis

A

Triggers signalling and results in change

28
Q

What do phagolysosomes contain

A

Products that can kill microbes

29
Q

Name products that phagolysosomes contain

A

Low ph/acidification
Hydrologic enzymes from lysozymes and proteases, love low ph
Oxidative attack
Antimicrobial peptides = defensins, Catholicidin

30
Q

What is oxidative attack

A

Employs reactive oxygen species = ROS and reactive nitrogen species = RNS = add more oxygen or nitrogen = toxic to pathogen phagocytosed

= damage microbial membranes and intracellular components

31
Q

How are ROS generated

A

Free radicals = ROS
Generated by phagocytes unique NADPH oxidase enzyme complex - or phagosome NADPH oxidase

32
Q

What does ROS production do

A

By NADPH oxidase increases oxygen consumption —> respiratory burst

33
Q

T OR F phagolysosome only important organelle for innate immunity

A

FALSEEEEEEEE
Important organelle for innate and adaptive immunity

34
Q

How is phagolysosome important organelle for innate immunity

A

Pathogen killing
Pathogen processes
Pathogen presentation to sensory cytoslic PRRS (some inside cells, tlr, nods)

35
Q

How is phagolysosome important organelle for adaptive immunity

A

Antigen degreadtion
Antigen processing
Antigen presentation onto mhc molecules

36
Q

What can phagocytes do

A

Clear cells have that undergone apoptosis
Dead/dying cells express damps —> eat me signals, bind to prrs

37
Q

What do some healthy cells express

A

Do not eat me signals = CD47

38
Q

Describe CD47

A

Will bind to signal regulatory protein alpha (SIRPalpha) on macrophage = transmits signals that inhibit phagocytosis

39
Q

WHAT DO TUMOUR CELLS EXPRESS

A

Elevated levels of CD47 —> tumour progression
Novel therapy = antibodies to block CD47 on tumour cells —> hopefully macrophage an phagocytose cancer cell

40
Q

DESCRibe neutrophils

A

Another cell capable of phagocytosis = inject and kill microorganisms
Not tissue resident = in circulation, recruited to site of infection

41
Q

What can neutrophils do

A

20-60% of neutrophils can produce extra cellular matrix called nets = neutrophil extracellular traps —> trap microorganisms and prevent spread

42
Q

What is pus

A

Result of dead and dying neutrophils

43
Q

Describe whole process of nets

A

Pamp binds prr = signals from prrs activate neutrophils = leads to intracellular signalling
Degradation of intracellular membrane of neutrophils then chromatins decondense
Cell bursts open and nets released = chromatins attached to some peptides
Nets can trap micoorganisms, stops spread

44
Q

Compare nets to reg cell

A

10-15x longer than actual cell

45
Q

Describe homeostasis - cns resident microglia

A

Cns resident microglia = macrophages of Brain responsible for establishing proper neuronal connections =
Participate in debris clean up, brain dev, memory, learning

46
Q

Describe disease multiple sclerosis

A

Not in homeostasis
Complex inflammatory disease characterized by myelin breakdown = lots of toxic debris built up in brain lesion micro environments

47
Q

What is required for cns repair

A

Microglia and peripheral infiltrates of macrophages participate in debris clean up —> various animal models show that this is required for cns repair
Helps homeostasis

48
Q

Describe receptor binding - microglia

A

Recognition of cell debris by mouse microglia via receptors leading to pseudopodia
Receptor binding important for initiating phagocytosis
If recpetor KO microglia = no pseudopodia formed

49
Q

Describe measuring phagocytosis in vitro

A

We want to know impact of diff conditions on phagocytosis
Dye substrate with a ph sensitive fluorophore —> only fluoresces under low ph conditions = phagolysosome
Fed substrate to macrophage s
Measured fluorescence of macrophages before and after diff condition

50
Q

Describe key points from research ex

A

Multiple steps involved in phagocytosis
Diff things may be affected if one step goes wrong, depends which

MIMM 214 (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions