In Vitro Cultivation of Blood Stream Trypomastigotes of Trypanosoma vivax without Feeder Cell Layers

Abstract

Bloodstream trypomastigotes (BSFs) of 2 clones (IL 1392 and IL 3671) of Trypanosoma vivax were cultured without feeder layers in 3 systems. System I: metacyclic-producing cultures of T. vivax IL 1392 were initiated with BSFs derived from infected mice at 27℃ in the presence of feeder layers using TVM-1 medium. Metacyclics harvested were then transferred to flasks containing feeder cells and maintained at 34℃ using TVM-22 medium. Under such conditions, the metacyclics transformed to BSFs. Bloodstream trypomastigotes which were then transferred to new flasks, continued to grow in HMI-162 medium without feeder cells. The maximum density of the BSFs and their shortest population doubling time were 3.5 x l0⁶ / ml and 13.5 h, respectively. System II: metacyclic-producing cultures of T. vivax IL 3671 were initiated with BSFs derived from infected cattle, without feeder layers at 27℃ using HMI-107 medium. Metacyclics were then transferred to the axenic culture conditions established in System I. They also transformed to BSFs and multiplied in HMI-162 and HMI-163 media. System III: cultures were initiated with proboscides of Glossina morsitans centralis which were infected with T. vivax IL 3671, without feeder layers at 34℃ using HMI-162 medium. Metacyclics emerged from the proboscides, transformed to BSFs and continued to grow in HMI-163 medium. The maximum density and the population doubling time of IL 3671 BSFs in HMI-163 medium were 1.8 x 10⁶ / ml and 16.1 h, respectively.