please Help!!!! . NK cells use two different types of receptors for distinguishi

ID: 201277 • Letter: P

Question

please Help!!!!

. NK cells use two different types of receptors for distinguishing healthy and infected cells. ey answer the following questions (a-e) about the two different types of receptors. o pt Receptor TypeaType a. What is the name of each type of receptor? b. What is the main ligand for each type of receptor? C. What is the response of the NK cell to engagement of each type of receptor? d. How do healthy cells differ from infected cells with respect to engagement of each type of receptor? Part e is on the next page

Explanation / Answer

Receptor type

Type I

Type II

Inhibitory receptor which recognize healthy cells

Activating receptor (cytotoxicity) which recognize infected cells

MHC I

Activating ligand (eg. HLA, NKG2D)

Inhibitory receptor recognize MHC-I ligand on the healthy cells that ‘switches off’ the NK cells and thus preventing the NK cells from killing the healthy cells

Activating receptor of NK cells recognize infected cells and interact with its ligand that ‘switches on’ the NK cells and ultimately NK cells kill the infected cells

HHealthy cells express enough MHC-I molecule to trigger a strong inhibitory effect in NK cells

Infected cells express more activating ligands that interact with NK cell receptors (activating receptors). This lead to activation of NK cells signals and kill the infected cells