Yersinia pseudotuberculosis Thermostable Toxin Dysregulates the Functional Activity of Two Types of Phagocytes in the Holothurian Eupentacta fraudatrix

The effect of a thermostable toxin of Yersinia pseudotuberculosis (in comparison with that of dexamethasone) on the functional activities of two types of phagocytes (P1 and P2) was studied in the holothurian Eupentacta fraudatrix. A high level of NO was shown to be a marker of intact P1 cells, while the high activity of arginase was a marker of P2 cells. The antioxidant defense in the P1 type was more pronounced than that of the P2 type. At the same time, the toxin inhibited the functional activity (generation of reactive oxygen species) of P1 phagocytes after 1 h of incubation and induced primarily the activity of P2 phagocytes, compared to that of P1 cells, after 24 h. In contrast to dexamethasone, which induced the transformation of the P1 phenotype into the P2 phenotype, the toxin promoted the mutual acquisition of the phenotype features by these two types of phagocytes. An analogy between the P1 and P2 phagocytes of the holothurian and M1 and M2 macrophages is discussed.