In Vivo Expression of Natural Killer Cell Inhibitory Receptors by Human Melanoma–Specific Cytolytic T Lymphocytes
Speiser DE., Pittet MJ., Valmori D., Dunbar R., Rimoldi D., Liénard D., MacDonald HR., Cerottini J-C., Cerundolo V., Romero P.
<jats:p>Natural killer (NK) receptor signaling can lead to reduced cytotoxicity by NK cells and cytolytic T lymphocytes (CTLs) in vitro. Whether T cells are inhibited in vivo remains unknown, since peptide antigen–specific CD8+ T cells have so far not been found to express NK receptors in vivo. Here we demonstrate that melanoma patients may bear tumor-specific CTLs expressing NK receptors. The lysis of melanoma cells by patient-derived CTLs was inhibited by the NK receptor CD94/NKG2A. Thus, tumor-specific CTL activity may be decreased through NK receptor triggering in vivo.</jats:p>