Multiplication of Toxoplasma gondii in Enucleated L Cells

Abstract

Toxoplasma gondii, the aetiological agent of human and animal toxoplasmosis, is considered to be an obligate intracellular parasite¹. To our knowledge, it has not been possible as yet to propagate this protozoan parasite outside of living susceptible nucleated cells; it has, however, been found to grow in the cytoplasm of a wide variety of tissue cultures^2,3. To date those attributes of the organism which are responsible for its fastidious requirements for multiplication remain obscure, and it has been suggested that T. gondii possesses a tropism for the host cell nucleus^4,5. Very little is known about the nucleo-cytoplasmic interactions in cells infected with this parasite. An autoradiographic study suggested that whereas the parasite incorporates ³H-uridine during intracytoplasmic multiplication, no uptake of ³H-thymidine takes place⁶. Electron microscopic autoradiography data suggested that T. gondii takes up ³H-thymidine during multiplication in abdominal monocytes of mouse⁷. Here we report the multiplication of T. gondii in enucleated L cells, which proves that nucleo-cytoplasmic integrity is not required for the intracytoplasmic multiplication of this parasite.