Reactions of the Hemocytes Cellular Immunity of the Mediterranean Mussel Mytilus galloprovincialis to Invasion by the Green Microalga Coccomyxa parasitica (In Vitro)

This paper is devoted to the study of the peculiarities of the cellular immune response of hemocytes of an object of mariculture fishery, Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1819), against cells of a potentially pathogenic green parasitic microalga, Coccomyxa parasitica R.N. Stevenson & G.R. South, 1974, in a comparative aspect with particles of Zymosan A and green microalgae Chlorella vulgaris f. suboblonga V.M. Andreeva 1975. Phagocytic capacity, hemocyte aggregation, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) during 3-hour incubation have been estimated. The results have shown that the hemocyte phagocytic activity and ROS production were highest against Zymosan A. The reaction was accompanied by a simultaneous decrease in MMP. The cells of C. vulgaris f. suboblonga occupied an intermediate position, causing a weaker stimulation of phagocytosis and a moderate decrease in MMP compared to Zymosan A. At the same time, incubation with C. parasitica resulted in a significant inhibition of phagocytosis and ROS production against the background of an increase in MMP, which may indicate the presence of mechanisms of suppression of cellular immune responses.