[Large-scale production of amastigotes by a human monoblastoid cell line]

In this study, a human monoblastoid cell line (TPH-1) was tested in vitro for the production of Leishmania amastigotes. The number of TPH1 cells increased with time and 6 days after promastigote infection the percentage of infected cells was around 45%. Pre-treatment of TPH1 cells with retinoic acid induced the cells to differentiate into unreplicating macrophage-like cells. Ninety per cent was parasitized 6 days after promastigote infection; the number of amastigotes quintuplied during this period of time; this result was irrespective of the Leishmania species used for experiments. Viable and infective parasites were obtained from treated and nontreated cells. TPH1 cells merit further consideration for research concerning new molecules active against Leishmania.