title: Incubation in mice provides a signal for the differentiation of Trypanosoma cruzi epimastigotes to trypomastigotes.
abstract: The differentiation of Trypanosoma cruzi epimastigotes into trypomastigotes was studied in diffusion chambers subcutaneously implanted in mice. Using epimastigotes of the Tulahuén strain, transformation was first evident at 16 h after implantation and reached its maximum (92% trypomastigotes) by 24 h. Shortly before their differentiation into trypomastigotes, epimastigotes were found to develop resistance to lysis by the alternative pathway of complement. Furthermore, implantation of stationary-phase (as opposed to log-phase) parasites resulted in the accumulation of large numbers of complement-resistant epimastigotes in the chambers. These observations suggest that epimastigotes pass through a complement-resistant transitional stage before differentiating into trypomastigotes and that transformation may require cell division. In a further series of experiments, epimastigotes recovered 7 h after implantation in mice were found to differentiate into trypomastigotes when cultured in vitro for an additional 17 h at 37 degrees C. This observation indicates that the events which trigger the morphologic transformation of epimastigotes into trypomastigotes can be dissociated operationally from the differentiation process itself.
mesh_terms: D000818:Animals; D002455:Cell Division; D003170:Complement Pathway, Alternative; D003165:Complement System Proteins / Q000502:physiology; D051379:Mice; D014349:Trypanosoma cruzi / Q000166:cytology* / Q000276:immunology / Q000502:physiology
chemical_list: D003165:Complement System Proteins