Single cell observation of calcium signals in class II specific killer T cells.

A confocal fluorescence microscope with an argon ion laser and a digital imaging fluorescence microscope were used to study calcium signals in class II-specific killer T cells after interaction with target cells. Here, we used two kinds of I-Ak specific allogeneic killer T cell clones, QM11 (CD8+) and QM56 (CD4+), and target cells, B10.A spleen cells (I-Ak) and B cell hybridomas (TP67.21, I-Ak). After interaction with target cells, the intracellular free calcium ion concentration ([Ca2+]i) in QM11 cells (CD8+) increased rapidly with short lag-times (several seconds). The [Ca2+]i in QM56 cells (CD4+), however, increased with much longer lag-times (hundreds of seconds). The results were consistent with previous findings that the cytolytic activity of QM11 cells (CD8+) was much greater than that of QM56 cells (CD4+).