Class crossover

See allHide authors and affiliations

Science  20 Dec 1996:
Vol. 274, Issue 5295, pp. 1983
DOI: 10.1126/science.274.5295.1983h

T cell receptors (TCRs) “see” foreign peptides complexed with either class I or class II major histocompatibility complex (MHC) proteins. Natural killer (NK) cells do not express TCRs but have activating and inhibitory receptors that bind to class I MHC molecules. Mandelboim et al. (p. 2097) studied such T cell clones that express the NK cell activating receptor (NKAR1). These T cells were isolated during NK cell cloning and were restricted to MHC class II responses. Proliferation of these T cells in response to superantigens increased by 300 to 900% in situations where the NKAR1 receptor could bind class I. This costimulation by class I proteins could help T cells initiate immune responses in the presence of limiting amounts of antigen.

Navigate This Article