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In vitro effect of human recombinant tumor necrosis factor on Entamoeba histolytica trophozoites
1Centre for The Study of Host Resistance, McGill University, Montreal, Quebec, Canada.
Abstract:
The effect of tumor necrosis factor (TNF) on E. histolytica trophozoites was examined by using three virulent (IP: 0682:1, HM-1: IMSS, 200: NIH) and one nonvirulent (DKB) strain of E. histolytica. Various concentrations of recombinant TNF were added to E. histolytica trophozoites and the total parasite numbers and their viability were periodically assessed by microscopic observation and trypan blue staining after incubation at 37 degrees C in a nonhumidified chamber. In this study, concentrations of 10(1)-10(6) units of TNF were used. Over a concentration range of 10(4)-10(6) units, the number of trophozoites was significantly lowered in the amoebic cultures containing TNF as compared to untreated controls. It was also found that the effect of TNF was dependent on the densities of both virulent and non-virulent strains of E. histolytica trophozoites in axenic conditions. TNF has no significant affect on the growth of amoebae at the lower starting number of amoebae. The amoebae cultured at the higher density were growth-inhibited significantly in comparison with the control groups. When the growth of the virulent and nonvirulent strains of amoebae was compared in TNF treated culture, it was found that TNF has an inhibitory effect on both the virulent and nonvirulent strans of E. histolytica.
Insights
Tumor necrosis factor (TNF) significantly inhibits the growth of E. histolytica trophozoites, particularly at higher parasite densities. This effect was observed across both virulent and nonvirulent strains, indicating TNF
Area of Science:
- Immunology
- Parasitology
- Cell Biology
Background:
- Entamoeba histolytica is an enteric protozoan parasite causing amoebiasis.
- Tumor necrosis factor (TNF) is a pro-inflammatory cytokine with diverse biological effects.
Purpose of the Study:
- To investigate the effect of TNF on the growth and viability of E. histolytica trophozoites.
- To determine if TNF's effect varies between virulent and nonvirulent E. histolytica strains.
Main Methods:
- Culturing virulent and nonvirulent E. histolytica strains in the presence of varying concentrations of recombinant TNF.
- Assessing parasite numbers and viability using microscopy and trypan blue staining.
- Incubation at 37°C in axenic conditions.
Main Results:
- TNF significantly reduced trophozoite numbers at concentrations of 10^4-10^6 units.
- The inhibitory effect of TNF was dependent on the initial density of E. histolytica trophozoites.
- Both virulent and nonvirulent strains exhibited growth inhibition when treated with TNF, especially at higher densities.
Conclusions:
- TNF exhibits a dose-dependent inhibitory effect on E. histolytica trophozoite growth.
- Parasite density influences the susceptibility of E. histolytica to TNF.
- TNF demonstrates potential as an agent against E. histolytica infections.