INHIBITION OF ANTI-GD3-GANGLIOSIDE ANTIBODY-INDUCED PROLIFERATION OF HUMAN CD8(+) T-CELLS BY CD16(+) NATURAL-KILLER-CELLS

The ganglioside GD3 has been described as a membrane component of human T cells which is involved in T cell growth. In the present study the activating function of GD3 for human CD4(+) and CD8(+) T cells was analyzed by five different monoclonal antibodies (mAb) directed against the GD3 molecule. Three mAb U5, Z21 and R24 induced strong proliferation of peripheral blood mononuclear cells and purified CD8(+) and CD4(+) T cells of normal donors containing less than 5% CD16(+) natural killer (NK) cells. In contrast to CD4(+) T cells, CD8(+) T cells proliferated only weakly in the presence of 15% CD16(+) NK cells. The proliferative response of purified CD4(+) and CD8(+) T cells (<5% NK cells) correlated with the antibody-dependent induction of integral and soluble interleukin-2 (IL-2) receptors and was reduced to 20% by an anti-IL-2 receptor antibody. Our results show, that the GD3 molecule represents an activation molecule for both CD4+ and CD8(+) T cells and that CD16(+) NK cells selectively inhibit anti-GD3 antibody-induced proliferation of CD8(+) T cells.