Demonstration of the role of cytophilic antibody in resistance to malaria parasites (Plasmodium berghei) in rats

Abstract

This paper reports studies on the immune response against P. berghei parasites by inbred rats. A macrophage-cytophilic antibody specific for malarial antigens was identified and characterized. Detection of the antibody on the macrophage surface was accomplished by the parasite adherence tests and by the indirect fluorescent antibody technique. Isolation and purification of the macrophage-cytophilic and opsonic antibodies from hyperimmune rat serum was accomplished by QAE[quaternary ammonium ethyl]-Sephadex A-50 elution chromatography. Purification of macrophage-cytophilic antibody was done by adsorption with and elution from syngeneic macrophages as well. Characterization of the cytophilic antibody as immunoglobulin G1 was done by immunoelectrophoresis and by Ouchterlony-type double diffusion in gel. Passive protection tests in weanling inbred rats demonstrated that the opsonizing antibody conferred some protection against P. berghei. The macrophage-cytophilic antibody was not protective alone but acted synergistically with the opsonizing antibody.