Lymphocyte Transformation Induced by Chemical Modification of Membrane Components

Abstract

Abstract Neuraminidase treatment of responder cells in indirect periodate or indirect neuraminidase-galactose oxidase (NGO) stimulation of rat lymph node cells (LNC) led to proliferative responses that were substantially greater and faster than those of controls. The indirect responses followed bicellular kinetics, i.e., the number of cells that initially responded was a function of the product of the number of stimulator cells and the number of responder cells in the cultures. Indirect NGO stimulation between allogeneic stimulators and responders was very similar to that between syngeneic cells, and neuraminidase treatment of responders had similar effects in both cases. The indirect mitogenic response between allogeneic cells completely abrogated the expected mixed lymphocyte reaction (MLR). Neuraminidase treatment of stimulators had little effect on the kinetics or magnitude of the rat one-way MLR. Treatment of responders, however, led to a faster and stronger response as compared with the normal MLR response. Treatment of both stimulators and responders was essentially the same as treatment of responders alone. These results, and those for indirect stimulation, suggest that the ability of responder cells to receive a mitogenic signal from stimulator cells is modulated by the amount of sialic acid on the responder cell surface. Although more blast cells were produced in indirect NGO cultures with neuraminidase-treated responders, the cytotoxic activity of these cultures was not enhanced over that produced in normal indirect stimulation. In fact, when referred to the extent of cellular proliferation in each culture, the cytotoxic activity produced by indirect stimulation was higher than that produced either by direct NGO stimulation or by indirect stimulation with neuraminidase-treated responders. Thus indirect NGO stimulation selectively activates cytotoxic cells. The additional cells that are activated by direct NGO stimulation, or after neuraminidase treatment of indirect responders, do not appear to be cytotoxic.