Mineral pitch stimulates humoral, cellular and innate immune responses in mice

Context: Mineral pitch (MP), a traditional medicine, is proposed to boost immunity in conditions that suppress Th1 cytokines such as AIDS/HIV, tuberculosis, leishmaniasis and cancer. Objective: This study investigates the immunoregulatory mechanisms of MP in innate, humoral and cell-mediated immunity. Materials and methods: Mice given MP (100, 200, 300 or 400 mg/kg, orally) for 10 consecutive days were immunized intravenously with goat RBC or ovalbumin, and investigated for plaque-forming cells (PFC), hemagglutination titer, hypersensitivity response, lymphocyte proliferation and macrophage function. Results: MP increased PFC (330.2 versus 182.2/10(6) splenocytes) in mice immunized with goat RBC and elicited ovalbumin-specific IgG titer at 400 mg/kg. Increase in Th1 immunity was correlated with the increased level of IFN-gamma (724 versus 470 pg/ml) and decreased IL-4 (96 versus 178 pg/ml). CD4(+)/CD3(+) ratio and delayed-type hypersensitivity response also increased to, respectively, 20.62 +/- 0.59 (versus 16.47 +/- 0.72) and 1.59 +/- 0.12 (versus 0.87 +/- 0.10 mm) in MP-treated mice. MP increased lymphocyte proliferation (11.14 +/- 0.60 versus 5.81 +/- 0.40 SI) and macrophage phagocyte response (0.24 +/- 0.02 versus 0.15 +/- 0.009), expressed as absorbance at 570 nm, but decreased nitrite production (17.4 +/- 1.10 versus 24.3 +/- 1.30 mu M/10(6) cells). We also observed an increased bone marrow cellularity (24.5 +/- 1.10 versus 17.10 +/- 0.70 cells/femur) and WBC count (12 667 +/- 377 versus 9178 +/- 213 cells/mm(3)) following MP treatment. There was no sign of toxicity at 400 mg/kg, 1/12th of reported LD50. Conclusion: MP elicits a dose-dependent Th1 immune response.