Question

How do natural killer (NK) cells recognize and respond to target cells during an Epstein-Barr virus infection?

a) NK cells bind complement fragments on the target cells.
b) NK cells engage MHC class I molecules on target cells.
c) NK cells use killer activation receptors (KARs) to detect stress molecules on target cells.
d) NK cells express immunoglobulins to recognize antigens on target cells.

Answer 1

Natural killer (NK) cells recognize and respond to target cells during an Epstein-Barr virus infection by using killer activation receptors (KARs) to detect stress molecules on the infected cells.

Step-by-step explanation:

Natural killer (NK) cells recognize and respond to target cells during an Epstein-Barr virus infection through the use of killer activation receptors (KARs) to detect stress molecules on the infected cells. Option c) is the correct answer. NK cells do not bind complement fragments on the target cells (option a)), engage MHC class I molecules (option b)), or express immunoglobulins to recognize antigens (option d)).

NK cells are able to respond to chemical signals and express the fas ligand, which binds to the fas molecule on the surface of the infected cell. This sends apoptotic signals, resulting in the killing of the infected cell and the pathogen within it.

Additionally, NK cells can recognize virally infected cells that downregulate their expression of MHC class I molecules, which is advantageous for the virus since it avoids recognition by cytotoxic T cells. NK cells have complementary activities with cytotoxic T cells against virally infected cells.