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Macrophage activation by Tetrahymena pyriformis. II. Active protein fractions from Tetrahymena
Abstract:
Water-soluble and 0.6 M KCl-soluble protein fractions prepared from Tetrahymena pyriformis, when inoculated into mice, could effectively induce activated macrophages having the ability to kill Toxoplasma gondii in vitro. This effect was not induced by other proteins tested, such as bovine serum albumin, pepsin from porcine stomach mucosa and chicken egg-white lysozyme, nor by muramyl dipeptide (MDP), a potent immunoadjuvant. Five fractions obtained by DEAE-Sephadex chromatography of the water-soluble protein fraction were compared with regard to induction of toxoplasmacidal activity in macrophages. The first peak was most effective for activation of macrophages. Five fractions obtained by chromatography of the 0.6 M KCl-soluble protein fraction were also examined and it was found that the first peak had the activity. No marked difference in activity was observed between the active fractions of water-soluble and 0.6 M KCl-soluble protein fractions. For practical use, we focused on the water-soluble active fraction. The minimum effective dose of the active fraction was 100 micrograms and the fraction could activate macrophages directly in vitro. Four fractions obtained by gel filtration of the active fraction on Sephadex G-200 were compared and the first peak had the activity. The first peak contained a single protein, revealed by SDS-polyacrylamide gel electrophoresis; its apparent molecular weight was 64,000.
Insights
Protein fractions from Tetrahymena pyriformis activate mouse macrophages to kill Toxoplasma gondii. This specific protein fraction, isolated via chromatography and gel filtration, demonstrated potent immunomodulatory activity.
Area of Science:
- Immunology
- Parasitology
- Cell Biology
Background:
- Macrophages play a crucial role in host defense against parasitic infections like Toxoplasma gondii.
- Identifying novel agents that can activate macrophages for enhanced pathogen killing is essential for developing new therapeutic strategies.
Purpose of the Study:
- To investigate the immunomodulatory potential of protein fractions derived from Tetrahymena pyriformis.
- To determine if these protein fractions can induce macrophage activation and enhance their ability to kill Toxoplasma gondii.
- To isolate and characterize the active protein responsible for macrophage activation.
Main Methods:
- Preparation and fractionation of water-soluble and KCl-soluble protein extracts from Tetrahymena pyriformis.
- DEAE-Sephadex chromatography and Sephadex G-200 gel filtration to isolate active protein fractions.
- In vitro assessment of macrophage activation and toxoplasmacidal activity in mice.
- SDS-polyacrylamide gel electrophoresis (SDS-PAGE) to determine the molecular weight of the active protein.
Main Results:
- Water-soluble and 0.6 M KCl-soluble protein fractions from Tetrahymena pyriformis effectively induced activated macrophages capable of killing Toxoplasma gondii in vitro.
- The most potent activity was observed in the first peak fractions obtained from both DEAE-Sephadex chromatography and Sephadex G-200 gel filtration.
- The minimum effective dose of the water-soluble active fraction was 100 micrograms, and it directly activated macrophages in vitro.
- SDS-PAGE revealed that the active fraction consisted of a single protein with an apparent molecular weight of 64,000.
Conclusions:
- A specific protein fraction from Tetrahymena pyriformis possesses significant immunomodulatory properties, capable of activating macrophages to combat Toxoplasma gondii infection.
- This protein, with a molecular weight of 64,000, represents a promising candidate for further investigation as a potential therapeutic agent against parasitic infections.
- The findings highlight the potential of microbial-derived molecules in stimulating innate immune responses for disease control.