IMMUNE-RESPONSE OF CRYPTOBIA-RESISTANT AND CRYPTOBIA-SUSCEPTIBLE SALVELINUS-FONTINALIS TO AN AEROMONAS-SALMONICIDA VACCINE

Brook charr Salvelinus fontinalis, both those susceptible and those re sistant to the pathogenic haemoflagellate Cryptobia salmositica, respo nded well to a commercially available Aeromonas salmonicida vaccine. T he proportion of susceptible and resistant charr which produced agglut inating antibody were similar, but resistant brook charr had higher ag glutination titres than susceptible brook charr. Concanavalin A stimul ated peripheral blood leucocytes of Cryptobia-resistant charr and the kinetic profiles suggest that maximal stimulation is dependent on mito gen concentration. Cryptobia-resistant brook charr displayed both cell -mediated and humoral responses suggesting that their immune functions are similar to those of Cryptobia-susceptible charr.