The limitation of growth of Trypanosoma musculi in vitro

Abstract

Trypanosoma musculi grow readily in vitro provided their growth is supported by mammalian cells. In the presence of murine spleen cells, or spleen cell-conditioned medium, the parasites increase by 100-fold, or more, in a period of 5-6 days. Growth ceases abruptly and death of the parasites soon follows. The reason for the termination of growth has been obscure and is the subject of this report. Termination of growth is not due to an immunological process; not even of ablastin affecting epimastigote reproduction. Instead it appears that other growth inhibitory substances are responsible. Culture medium, collected from spent cultures on day 8 after initiation, inhibits T. musculi growth in fresh medium in dose-dependent fashion. No inhibitory substances were present in medium collected earlier, during the phase of rapid parasite growth. These inhibitory substances appeared to be derived from the parasites rather than the cocultivated spleen cells. © 1987.