The immune system of cyprinid fish = Immunologie van de karper

This study deals with several aspects of the immune system of cyprinid fish.<p>Some observations on the development of cellular and humoral responsiveness in rosy barb <em>(Barbus conchonius)</em> are described in appendix I. A humoral anti-sheep red blood cell (SRBC) response was demonstrated in 3-4 months old animals, but the peak response was lower than in adult (9 months old)animals (90 and 700 plaque forming cells (PFC)/10 ⁶white cells respectively). The scale transplantation technique was used for studying cellular immunity. No significant difference in the median survival time (MST) of allografts was observed in 6 and 9 months old animals (8.0 and 8.3 days respectively). It is concluded that 3-4 months old animals have the competence to respond to SRBC, but the humeral immune system is not fullgrown till 5-6 months later. Cellular immunity has cone to complete maturation at 6 months or earlier.</p><p>For several reasons carp <em>(Cyprinus carpio)</em> was used in the second part of this study. First the plaque assay of Jerne had to be modified for carp in order to monitor the humoral immune response at the level of antibody forming cells (appendix II). Serum of bream <em>(Abramis brama)</em> turned out to be a more reliable complement source than allogeneic carp serum. Using the plaque assay, the kinetics of the anti-SRBC response has been studied (appendix III) . The kidney (pro- and mesonephros) appeared to be a major antibody producing organ in carp. Spleen accounted only for 5% of total PFC numbers. At high temperatures (20-24°C) carp are able to mount clear-cut primary and secondary responses. At lower temperatures (10-18°C) the peak of the primary response was delayed, but the magnitude of the response remained the same. The temperature-peak day relationship indicated that there are at least 2 steps in the primary immune response of carp differing in temperature sensitivity. The anamnestic character of the secondary response was gradually lost at lower temperatures. Therefore the development of immunological memory is probably also temperature dependent. In appendix IV the effect of antigen dose and route of administration on the development of immunological memory was studied. Immunization with low antigen doses along the intramuscular route was optimal for the formation of immunological memory. The capacity to mount an enhanced secondary response was specific for the priming antigen and lasted for at least 10 months.</p><p>The effect of the antibiotic oxytetracycline (oxyTC) upon the immune system of carp was investigated (appendices V and VI). Oral administration of oxyTC had no influence upon the MST of allografts, but injections with oxyTC significantly prolonged the MST from 8.5 till 11-20 days. The suppressive effect of oxyTC on humoral immunity was clearly demonstrable at the level of antigen binding and antibody producing cells. PM numbers were reduced up to 95% during a primary response. Secondary responses were not significantly inhibited by oxyTC.</p><p>A careful use of this drug is recommended since oxyTC can exert immunosuppressive effects during a primary response.