Introduction: Cell culture is an important method for isolating Toxoplasma gondii to make clinical diagnosis or for biotechnological purposes.
Objective: The percentage of invasion and production levels of T. gondii was determined for THP1 and Vero cell lines.
Materials and methods: The growth conditions for T. gondii in Vero and THP1 cell lines were determined by counting in hemocytometer chamber. The percentage of invasion of T. gondii in THP1 and Vero cells was determined by flow cytometry in different cell/tachyzoite ratios: 1/5, 1/20, 1/50. The growth performance index of the T. gondii RH strain and the CIBM1 isolate was calculated for THP1 cells.
Results: Vero cells multiplied faster than the THP1 cells, showing an exponential and a sigmoidal growth curve respectively, within a period of 7 days. The CIBM1 isolate infected the THP1 cells in three different parasite concentrations: 1/5, 1/20 and 1/50, with invasion percentages in THP1 cells of 57.1%, 15.5% and 12.2% and for the Vero cells 25.3%, 17.8% and 8.8% respectively. The RH strain of T. gondii had the lowest invasion percentage with 32.6%, 14.8% and 8.1% in THP1 cells and 22.3%, 14.1% and 3.4% in Vero cells.
Conclusions: The CIBM1 isolate had a higher yield than the RH strain of T. gondii in THP1 cells. THP1 cells were indicated to be a good model for the study of invasion and for the assays of new pharmacological candidates against T. gondii.