Effect of Sinorhizobium meliloti lipopolysaccharide on blood cell composition in the experiment

Abstract

Lipolysaccharides (LPS, endotoxins) of gram-negative bacteria have a pronounced biological activity, including therapeutic activity; however, there is no such data for S. meliloti. Aim. To conduct an experimental study of hematopoietic activity of four lipopolysaccharide fractions isolated from S. meliloti under induced immunodeficiency in mice. Methods. 7 groups of 10 laboratory mice each were formed: group 1, intact mice (control 1); groups 2-7, mice with immunodeficiency induced by a single intraperitoneal injection of cyclophosphamide Mice of group 3 were daily injected with a comparison agent, Licopid^® (Chemical name: [4-O-(2-acetylamino-2-deoxy-β-D-glucopyranosyl) -N-acetylmuramyl] -L-alanyl-D-α-glutamyl amide; single dose, 0.1 ml (0.05 mg/ml)) for 21 days starting one day after the induction of immunodeficiency Mice of groups 3-7 were injected with the studied S meliloti LPS fractions, LPS-1, LPS-2, LPS-3, and LPS-4, respectively (single dose, 0.2 ml (10 pg/ml)) Immunodeficient mice of group 2 received neither the comparison agent, Licopid^® nor LPS fractions The mice were euthanized at 21 days Weight characteristics of animal organs and white blood count were studied Results. Administration of Licopid® to mice with secondary experimental immunodeficiency was associated with decreased count of stab neutrophils and monocytopenia; LPS-1 fraction increased the count of segmented neutrophils; LPS-2 decreased the count of stab neutrophils and induced lymphocytosis; LPS-3 decreased the count of stab neutrophils and induced lymphocytosis associated with a significant increase in the count of segmented neutrophils; LPS-4 induced basophilia, decreased count of stab neutrophils, and lymphocytosis associated with a significant increase in the count of segmented neutrophils. Conclusion. Sinorhizobium meliloti LPS fractions exerted modulating effects similar to the mechanisms of “emergency myelopoiesis” in the physiological course of bacterial infections.