| Abstract: | Human leukaemia and lymphoma cell lines were investigated as stimulating cells in an allogeneic mixed lymphocyte response. Purified T cells and unfractionated mononuclear cells from normal donors were used as responders. The cell lines fell into three groups: (i) those which stimulated allogeneic responder T cells in the presence or absence of accessory (non-T) cells; (ii) those which stimulated T cells only in the presence of accessory cells; and (iii) those which failed to stimulate in either case. The accessory function was provided by adherent cells and non-adherent, non-T cells. There was no correlation between the stimulatory capacity of these cell lines and the presence of serologically defined HLA-DR determinants. These results are discussed in the context of the current two-signal hypothesis for T-cell activation. |
