Immunosuppressive effect of purified pyocyanine pigment on T-lymphocytes viability against experimental infection with hydatid cyst protoscolices

Background: The effect of pyocyanine pigment, which was isolated and purified from Pseudomonas aeruginosa, on specific lymphocytes viability inside the body of white male Balb/c mice against the experimental secondary hydatidosis and the infectivity of protoscolices was studied in comparison with negative control mice groups, phosphate buffered saline (PBS) and positive control group (immunoferon). Materials and methods: Four groups of male Balb/c mice were intraperitoneally (IP) inoculated with four purified concentrations of pyocyanine (25, 50, 75, 100?m/ml). Seven days later, they were given the same concentrations as a booster dose of the pigment, then 7 days later they were intraperitoneally infected with 2000 protoscoleces /mL (PBS) as a challenge dose. The fifth group was intraperitoneally inoculated with 1ml of sterile PBS and used as a negative control group, while the sixth group was intraperitoneally inoculated with 100?mg/ml immunoferon and received the challenge dose of 2000 protoscoleces/ml PBS and served as the positive control group. Results: The concentrations of 50, 75 and 100?m/ml of this pigment had suppressive effect on these specific immune response cells. This effect was statistically significant (p < 0.01) after six weeks from the challenge dose with intraperitoneal protoscolices infection. This effect revealed that the protoscolices infectivity increased due to suppression viability of T lymphocytes, while the immunoferon showed a significant stimulation of these specific cellular cells, which decrease the protoscolices infectivity in comparison with higher pigment concentrations. Conclusion: Pyocyanine is a toxic pigment causing suppression of T-cells activity, especially at higher concentrations which allow protoscolices development and growth