Cyst Formation by Toxoplasma gondii (RH Strain) in Vitro

Abstract

Evidence is presented that immunologic mechanisms can influence the development ofToxoplasmacysts. The RH strain ofToxoplasma gondiiproduced cysts in tissue cultures (monolayers of rabbit corneal endothelial cells) when antitoxoplasma rabbit serum and fresh dyetest-negative guinea-pig serum were added to the medium. Immune rabbit serum alone also mediated a minimal amount of cyst formation by the organism, but fresh guinea-pig serum alone did not. The possible modes of action of the various immune components are presented, and their theoretical relationship toToxoplasmacyst formation in infected eye tissues is discussed.