Natural Killer cells

Question 1

NK cells: form of immunity, basic functions (no real details)

Answer 1

innate immunity; recognize ligans on infected cells or cells undergoing other types of stress

kill infected or stressed cells

eliminate reservoirs of infection and thus release intracellular pathogens for phagocytosis

Question 2

NK cells respond to WHAT CYTOKINE and release WHAT CYTOKINE

think reciprocity

Answer 2

respond to IL 12 and release IFN-gamma

so a macrophage will release IL 2, stimulate IFN gamma

IFN gamma activates the mac to kill phagocytized microbes

Question 3

Activation and Killing mechanism of NK cell (the important ones in blue)

Answer 3

activated receptors on NK recognize receptors on target cells and activate protein tyrosine kinases (PTKs)

Question 4

NK cell activating receptors are called

Answer 4

killer cell immunoglobin (Ig like) receptors KIRs

Question 5

The way NK cells avoid killing class 1 MHC expressing healthy cells

Answer 5

inhibitory receptors recognize class 1 MHC molecules
and activate protein tyrosine phosphatases (PTP)
these inhibit the PTKs

PTPs inhibit PTKs!

Question 6

Ramifications of any I MHC inhibitor

Answer 6

NK cells can’t recognize them as self-molecules, and NK cells are then activated to kill

Question 7

KARs

Answer 7

Killer Activation Receptors on NK cells, many kinds

Question 8

NCR

Answer 8

Natural cytotoxicity receptors, these mediate NK killing and release IFN gamma