Phagocytes & Phagocytosis

Question 0

opsonins

Answer 0

“bridging” molecules that attach to phagocyte and microorganism

Question 1

Mononuclear Phagocyte System (MPS)

Answer 1

macrophages in spleen, liver & bone marrow

Question 2

Critical step in phagocytosis

Answer 2

ATTACHMENT of phagocyte to microorganism

Question 3

Types of Opsonins

Answer 3

1. Lectins
2. C3b
3. IgG

Question 4

Lectins

Answer 4

proteins that bind to mono- & disaccharides.
common in bacterial & fungal cell walls

ex: C-Reactive Protein (CRP) & Mannose-Binding Lectin (MBL)

Question 5

C3b

Answer 5

from Complement.

attaches to microbial surfaces & receptors on phagocytes

Question 6

IgG

Answer 6

phagocyte’s have Fc Receptors (FcR) that these Abs bind to after they’ve bound Ags

Question 7

Categories of Killing Mechanisms

Answer 7

1. Oxygen-Independent
2. Oxygen-Dependent
3. Nitric Oxide-Dependent

Question 8

Oxygen-Independent killing mechanism

Answer 8

lysosomes (w/ lots of antimicrobial substances) fuse w/ phagosome (phagosome-lysosome fusion)

Question 9

Oxygen-Dependent killing mechanism

Answer 9

done by reactive oxygen intermediates (ROI) generated during respiratory bursts.

Question 10

Reactive Oxygen Intermediates (ROI)

Answer 10

kill by modifying enzymes & nucleic acids.

Question 11

respiratory burst

Answer 11

metabolic pathway activated during phagocytosis where molecular O2 is converted to reactive forms that damage microorganisms

Question 12

most lethal ROIs

Answer 12

superoxide ion (O2-)
hypochlorite (OCl-)
hydroxyl radical (.OH)

Question 13

Nitric Oxide-Dependent killing mechanism

Answer 13

NO radicals kill by modifying enzymes & nucleic acids.
NO radicals made in macrophages.
NO radicals kill things resistant to other 2 killing mechanisms

Question 14

Neutrophil functions

Answer 14

PAMP/DAMP Recognition, Pathogen Destruction, some Signaling Molecule function

recruited to tissue early

Question 15

Macrophage Functions

Answer 15

Sentinel, PAMP/DAMP Recognition, Signaling Molecules, Cell-Cell Comm., Pathogen Destruction

recruited to tissue late

Question 16

Natural Killer (NK) cells

Answer 16

lymphocytes that are part of Innate I.S.

also called “large granular lymphocytes” (LGL)

Question 17

Location of NK cells

Answer 17

tissues & recruited to inflamed tissues from blood

Question 18

receptors that _____ NK cells in recognition

Answer 18

Activate: recognize stressed cells & IgG (via FcR)
Inhibit: recognize normal proteins on all cells (form of MHC class 1)

Question 19

NK cell functions

Answer 19

1. kill cells infected w/ intracellular parasites (no replication allowed)
2. kill genetically transformed cells (cancer)
3. Secrete interferon-gamma (activate macrophages)