A Combination of Muramylpeptides from Gram-Negative Bacteria Corrects Hematological and Immunological Disorders Induced by Cyclophosphamide

Combination of Muramylpeptides from Gram-Negative Bacteria Corrects Cyclophosphamide-Induced Disorders of Hematopoiesis and Spleen Cell Composition in Mice with B16 Melanoma

We studied the effect of a combination of three muramylpeptides from gram-negative bacteria (Polymuramyl) on hematological parameters, morphology of the spleen, and serum cytokine level in mice with B16 melanoma treated with cyclophosphamide. Intraperitoneal administration of cyclophosphamide to tumor-bearing animals sharply reduced the number of leukocytes, especially neutrophils, in the blood and depleted the cellular composition of the spleen white pulp. Subsequent three daily intramuscular injections of Polymuramyl in doses of 70 and 860 ng/mouse for 3 days, as well as subcutaneous injection of the reference drug filgrastim (granulocytic CSF) in a dose of 12 μg/mouse partially corrected hematopoietic disorders and restored the cellular composition of the spleen. Granulocytic CSF more effectively replenished the content of mature neutrophils in the blood, while Polymuramyl restored the content of stab neutrophils. In contrast to granulocytic CSF, administration of Polymuramyl was followed by an increase in the level of granulocyte-macrophage CSF and a tendency to an increase in the serum content of IL-6, which indicates the involvement of these cytokines in the hematopoietic activity of Polymuramyl.

Effect of Cathepsine L1 on Transformation of Malignant Melanoma B16 Cells into Melanocytes

We studied the effects of cathepsins produced by immunocompetent cells of intact mice, mice with B16 melanoma, mice with removed B16 melanoma, and mice with removed Ehrlich carcinoma on the growth of B16 melanoma. Incubation of B16 melanoma cells with cathepsins from immunocompetent cells of intact mice, mice with B16 melanoma, and mice with removed Ehrlich carcinoma did not affect tumor growth. Incubation of B16 melanoma cells with cathepsin from immunocompetent cells of mice with removed B16 melanoma was followed by complete loss of malignancy by these cells. Melanoma cells formed no tumor node within at least 1 year after transplantation, though exhibited high proliferative activity and formed pigmented nevi. The formation of a nevus by B16 melanoma cells is described for the first time. The existence of a mechanism regulating proliferation of malignant cells in the tumor-bearing host was hypothesized. Studies of this mechanism are expected to promote the development of new methods for the treatment of tumors.

Dose-Dependent Effect of Bacillus sp. Metabolites from Permafrost on Lymphocyte Differentiation in the Thymus

We studied the effect of a single intraperitoneal injection of metabolites from Bacillus sp. M3 strain isolated from permafrost (from 5×10³ to 50×10³ microbial bodies) on differentiation of T cells in the thymus of F1(CBA/Black-6) mice. On day 21 after the injection of metabolites, a dose-dependent decrease in the level of CD34+CD44+ and an increase in the number of CD34⁺CD44-, CD25-TCR⁺, CD25⁺TCR^+max, CD4⁺CD8-, CD4-CD8⁺, and CD44⁺TCR⁺ lymphocytes were observed in the thymus. The increase in thymus level of mature (CD25⁺TCR^+max) and migration-ready (CD44⁺TCR⁺) T cells in combination with a moderate decrease in the level of T cell precursors entering the thymus from the bone marrow (CD34⁺CD44⁺) can indicate a modulating influence of Bacillus sp. metabolites on functional activity of the thymus aimed at maintenance of the T cell balance in the body.