Which statement is not true for Natural killer (NK) cells? -triyambak.org

Practice Questions

TLS Online TPP Program

#Question id: 16147

#Unit 4. Cell Communication and Cell Signaling

Natural killer (NK) cells are lymphoid cells that are closely related to B and T cells. However, they do not express antigen specific receptors and are considered part of the innate immune system.
They are distinguished by the expression of a surface marker known as NK1.1, as well as the presence of cytotoxic granules. Once referred to as “large granular lymphocytes” because of their appearance under a microscope.
NK cells constitute 5% to 10% of lymphocytes in human peripheral blood. Th ey are effi cient cell killers and attack a variety of abnormal cells, including some tumor cells and some cells infected with virus.
They distinguish cells that should be killed from normal cells in a very clever way: by “recognizing” the absence of MHC class II, which is expressed by almost all normal cells, but is specifically down-regulated by some tumors and in response to some viral infections.