INHIBITION OF ANTIBODY PLAQUE FORMATION BY SENSITIZED LYMPHOID CELLS: RAPID INDICATOR OF TRANSPLANTATION IMMUNITY.

Spleen cell suspensions obtained from mice immunized with sheep erythrocytes form localized zones of hemolysis ("antibody plaques") when incubated in agar gel containing sheep red blood cells and complement. Plaque formation can be inhibited by prior incubation in vitro with spleen cell suspensions from another strain of mice previously sensitized to the first by spleen cell transplant. Suppression of plaque formation was found to be quantitatively related to the number of cells incubated and apparently reflected a homograft reaction in vitro of one spleen cell population against another. Plaque inhibition may be a useful indicator of transplantation immunity.