Syngeneic mixed lymphocyte reaction (SMLR) with dendritic cells: direct visualization of dividing T cell subsets in SMLR.

Syngeneic mixed lymphocyte reaction (SMLR) has been considered to represent T cell response to self antigens. In this study using stimulator dendritic cells (DC), we analyzed cellular components responding to the syngeneic DC. It was shown that the predominant dividing cells were CD8(+) T cells although the response of CD4(+) T cells was essential for initiation of SMLR. In spite of the vigorous proliferation and expression of several activation markers, these SMLR-activated CD8(+) T cells hardly killed syngeneic targets and most of the CD8(+) T cells produced no interferon-gamma upon restimulation with DC. Furthermore, in SMLR where CD8(+) T cells were absent or inhibited, a considerable proliferation of CD4(-) CD8(-) double negative-T cells that included TCRalpha/beta(+) natural killer-T cells (NKT cells), TCRgamma/delta(+) NKT cells and TCRgamma/delta(+) T cells was observed.