Characterization of NKT-cell hybridomas expressing invariant T-cell antigen receptors.

Two natural killer T (NKT)-cell hybridomas were established by fusing sorted NKT cells with BW1100 thymoma cells. The first hybridoma line, 1B6, was CD48, whereas the second one, 2E10, was CD48. Initial characterizations revealed that both cell lines expressed an invariant T cell antigen receptor, which could be readily detected with a-galactosylceramide-loaded CD1d : Ig fusion protein (a-GalCer/CD1d). Sequence analyses of the a and b chains of the T cell receptor V genes revealed that 1B6 and 2E10 cells expressed Va14Ja18/Vb8.2Db2Jb2.7 and Va14Ja18/Vb8.1Db1Jb1.1, respectively. When these hybridoma cells were stimulated with immobilized anti-CD3 monoclonal antibodies, a-GalCer/CD1d, or a-GalCer in the presence of antigen-presenting cells, they produced IL-4 and IFN-g. The expression levels of CD69, CD154, and CD178 were concomitantly up-regulated on both hybridomas upon stimulation. Because it is difficult to isolate a sufficient number of NKT cells, these hybridomas should provide useful platforms to study a variety of functions of NKT cells. 〔J Clin Exp Hematopathol 47 (1) : 1-8, 2007〕