Kinetics of in vitro phagocytosis by cells from head-kidney of common carp, Cyprinus carpio.

Abstract

Whole cell suspensions from ten one-year-old carp were used for phagocytosis tests with opsonized sheep red blood cells (SRBC) within a duration of 24 hrs. The results were evaluated from the counts of smears stained for peroxidase activity and by Giemsa stain.The phagocytosing cells were of two lines : the macrophages and the neutrophils. A certain cell form resembling round thrombocytes could not be classified. The macrophages ingested the most SRBC/cell. The average number of ingested SRBC increased continuously in the macrophages, but remained low in the neutrophils. Increase in the total number of phagocytosed SRBC was the fastest in the first hour of incubation with a relatively slow progress in the succeeding hours. However, a second rise in the total number of phagocytosed SRBC occurred between the 12th and 24th hour of incubation. A strongly increasing number of juvenile neutrophil forms participating in the phagocytosis was observed during this period resulting in both the number of phagocytosing neutrophils and the number of phagocytosed SRBC by the neutrophils surpassing significantly those figures for the macrophages.Data on the phagocytosis by the neutrophils are assumed to reflect an important initial functional phase of the unspecific defence mechanism.