Identification and characterization of Xenopus CD8+ T cells expressing an NK cell-associated molecule

✍ Scribed by Laura Rau; Jennifer Gantress; Alisa Bell; Rebecca Stewart; Trudy Horton; Nicholas Cohen; John Horton; Jacques Robert

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 240 KB
• Volume: 32
• Category: Article
• ISSN: 0014-2980
• DOI: 10.1002/1521-4141(200206)32:6<1574::aid-immu1574>3.0.co;2-4

✦ Synopsis

Growing evidence suggests that some immune responses are mediated not only by conventional and distinct NK cells and CTL, but also by T cell subsets expressing NK receptors and NK cell-associated molecules. Consistent with our previously published finding that the mAb 1F8 identifies non-T/non-B cells in Xenopus that effect NK-like killing in vitro, we now report that in vivo treatment with this mAb impairs rejection of transplanted MHC class I-negative tumor cells. However, we also find that the NK cell-associated molecule recognized by mAb 1F8 is expressed by a minor population of CD8+ T cells, in which fully rearranged TCRbeta mRNA of at least three different V families can be identified, by contrast, 1F8+/CD8- (NK) cells lack such TCRbeta message. Additionally, the expression of the NK cell-associated molecule can be induced in vitro by a transient submitogenic stimulation of naïve CD8+ T cells with PMA and ionomycin. Such induced expression of 1F8 also occurs in alloantigen-activated CTL and is coincident with a down-regulation of MHC-specific cytotoxicity. Taken together, these new data suggest that regulation of CD8+ T cell activity involving NK cell-associated molecules is a general and evolutionarily ancient phenomenon.