Unprimed spleen cell populations recognize macrophage-bound antigen with opposite net electric charge.

Previous studies have demonstrated an inverse charge relationship between the net electrical charge of antigen and the responding cells. In the present study we attempted to establish whether this phenomenon holds also for the primary recognition phase of cell-mediated immunity, when the involvement of the macrophage in presenting antigen is obligatory. Normal spleen cells were fractionated over negatively and positively charged columns. The fractionated cell populations, as well as the original cells, were sensitized in vitro on macrophage monolayers that were pulsed either with the basic encephalitogenic protein of myelin or with the acidic copolymer poly(Glu50,Tyr50). Cells eluted from glass bead columns(i.e., the more negative cells) could be sensitized only with the basic antigen, while cells eluted from poly(L-lysine)-glass bead columns (i.e., more positive cells) could be sensitized only to the acidic antigen. Thus, in delayed type hypersensitivity the inverse charge relationship prevails also for the primary immunological recognition of antigen bound to macrophages.