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In the central nervous system and in the liver, the macrophage populations are represented exclusively by descendants of the hematopoietic progenitor cells of the yolk sac. The reasons for such differential distribution of macrophages are not fully understood. We found that, as can be judged by corresponding changes in the expression of CD86 and CD163 markers, the transient macrophages of monocytic lineage are more sensitive to activating stimuli. The two macrophage populations have distinct patterns of gene expression, which is particularly noticeable for M1- and M2-associated genes. For instance, Kupffer cells more readily develop and longer maintain the elevated expression levels of Il4, Il10, and Il13 upon the activation; by contrast, the macrophages of monocytic lineage express Il1b, Il12a, and Tnfα upon the activation. The obtained results allow us to conclude that the in vitro activated Kupffer cells of the liver are committed to M2 phenotype, whereas the in vitro activated monocyte-derived macrophages show a typical M1 behavior. These observations are likely to reflect the situation in the in vivo microenvironments.

Macrophages of mammals are a heterogeneous population of cells. This applies both to the functional parameters of macrophages and to the sources of their development. The comparative characteristics of macrophages of embryonic origin on the example of Kupffer cells and macrophages of bone marrow origin on the example of macrophages of monocyte derivatives were carried out. Cultures of Kupffer cells and macrophages of monocytic origin were obtained. The phenotype, profile of gene expression of native macrophages activated in direction M1 and M2 was studied. The phenotype of isolated cultures is characterized by methods of immunocytochemistry, flow cytometry. Gene expression was studied by real-time polymerase chain reaction. Under the influence of inducing factors, the phenotype of two populations of macrophages changes in a similar way: under the influence of M1-factors, the synthesis of CD86 and iNOs is activated in cells, under the influence of M2 - CD163 and Arg1. In Kupffer cells, expression of anti-inflammatory cytokines - il4, il13, is more pronounced, and in macrophages of monocytic origin of pro-inflammatory cytokines - il1b, tnfa, il12a. The induction of the genes of proinflammatory cytokines in Kupffer cells is slower compared to macrophages of monocytic origin.