ENTRY AND SURVIVAL OF LEISHMANIA-AMAZONENSIS AMASTIGOTES WITHIN PHAGOLYSOSOME-LIKE VACUOLES THAT SHELTER COXIELLA-BURNETII IN CHINESE-HAMSTER OVARY CELLS

Coxiella burnetii, a rickettsia, and Leishmania amazonensis, a protozo an flagellate, lodge in their host cells within large phagolysosome-li ke vacuoles. In the present study, C, burnetii-infected Vero or CHO ce lls were superinfected with L. amazonensis amastigotes to determine if these parasites can home to and survive within heterologous vacuoles. Six hours after superinfection, Leishmania amastigotes were located a lmost exclusively within large Coxiella-containing vacuoles. Thereafte r, the numbers of parasites in the vacuoles increased at the same rate as those in cells infected with L. amazonensis alone. Furthermore, in cultures shifted to 25 degrees C, some of the amastigotes transformed into promastigote-like forms that moved their flagella within the ado ptive vacuoles. Thus, L. amazonensis amastigotes not only entered Coxi ella vacuoles, most likely by fusion of donor and recipient vacuoles, but temporarily survived, differentiated, and replicated therein, This appears to be the first account of the temporary cohabitation of two living pathogens within the same vacuole in a mammalian cell.