EN
The effect of saprolegnia infection, therapy using malachite green and application of Lewamisole as a stimmulant on the activity of cellular protective mechanisms in the carp was evaluated. Three methods were used in experimentations: the NBT to determine a metabolic activity of neutrophils, rosette E test to check a number of rosettes produced by T lymphocytes, cytochemic method to detect the presence of alpha-naphylesterase in membranes of T lymphocytes. Moreover, a total number of blood leukocytes and neutrophils was determined. It was found that: 1) fungal infection stimmulates immunological cellular reactions 2) Lewamisole appeared to be an effective immunostimulant which affected positively the course and descent of infection 3) in practice the fish may be bather in Lewamisole solution insted of intraperitoneal injection of this immunostimulant because both ways of this drug application gave a comparable results 4) immunosuppresive action of malachite green due to some discrepancies of results (table 1) may not be univocally stated.