Heterogeneidad en la metaciclogénesis in vitro de clones derivados de una cepa costarricense de Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae)

the in vitro metacyclogenesis was evaluated in three clones derived from the costa rican tc-4 strain of trypanosoma cruzi as a criterion of biological heterogenity between clones and their parental strain. the clones were obtained from colonies that resulted from culturing the t. cruzi strain in 40% blood agar. these clones were named tc-4 á, tc-4 β, and tc-4 e and were maintained in diphasic 40% blood agar with 3,7% brain hearth infusion as the liquid phase. the metacyclogenesis was induced by incubating epimastigotes in triatomine artificial urine suplemented with proline (tau + p) at a constant temperature (27oc). the progress in the metacyclogenesis was monitored daily and the ratio of metacyclic trypomastigotes/epimastigotes, the percent of trypomastigotes, and the concentration of metacyclic trypomastigotes (mt/ml) were determined. variability was evaluated using anova tests for repeated measures (a: 0,05). the indicators of metacylogenesis showed the highest values between 72 and 96 hours after the beginning of the experiment. in this interval there were significant statistical differences between some of the cellular systems (p < 0,05). these observations could suggest that the clonal composition of each strain of t. cruzi can determine the infectivity for the vertebrate host