Response of Ig-positive cells to Goussia carpelli (Protozoa: Apicomplexa) infections in carp (Cyprinus carpio L.).

The kinetics of Ig-positive cell populations in carp tissues was followed during an infection with the gut dwelling coccidian Goussia carpelli Léger et Stankovich, 1921. In cell suspensions of the anterior and posterior sections of the intestine, the proportion of Ig-positive cells increased with the development of the coccidia and peaked during oocyst formation at day 15 post exposure. These results suggest a reaction of the local mucosal immune system. In cell suspensions of pronephros the proportion of Ig-positive cells increased as well, indicating that a systemic immune response was also induced against this intestinal coccidian parasite of carp.