Characterization of NKT-cell Hybridomas Expressing Invariant T-cell Antigen Receptors

Abstract

Two natural killer T (NKT)-cell hybridomas were established by fusing sorted NKT cells with BW1100 thymoma cells. The first hybridoma line, 1B6, was CD4⁺8^-, whereas the second one, 2E10, was CD4^low8^-. Initial characterizations revealed that both cell lines expressed an invariant T cell antigen receptor, which could be readily detected with α-galactosylceramide-loaded CD1d : Ig fusion protein (α-GalCer/CD1d). Sequence analyses of the α and β chains of the T cell receptor V genes revealed that 1B6 and 2E10 cells expressed Vα14Jα18/Vβ8.2Dβ2Jβ2.7 and Vα14Jα18/Vβ8.1Dβ1Jβ1.1, respectively. When these hybridoma cells were stimulated with immobilized anti-CD3 monoclonal antibodies, α-GalCer/CD1d, or α-GalCer in the presence of antigen-presenting cells, they produced IL-4 and IFN-γ. 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]