VACCINATION OF RACING GREYHOUNDS - EFFECTS ON HUMORAL AND CELLULAR-IMMUNITY

Greyhound kennel owners frequently employ multiple vaccination schedul es in an attempt to reduce financial losses incurred as a result of in fectious diseases. In order to determine the effects of multiple vacci nation schedules on the immune system of racing greyhounds, three litt ers of greyhound pups raised in laboratory conditions were divided int o two groups and subjected to either a maximum or a minimum vaccinatio n schedule. Blood samples were collected biweekly for 6 months beginni ng at 2 weeks of age and analyzed to establish 'baseline' values for t he lymphatic system of greyhounds. Lymphocyte transformation, total an d differential leukocyte counts, and flow cytometry were used to evalu ate cellular immunity. Humoral immunity was evaluated using serum neut ralization and hemagglutination inhibition tests. Proliferation of per ipheral blood lymphocytes in response to the mitogen concanavalin A (C on A) was higher for the maximum vaccination groups. The frequency dis tribution of circulating CD4 and IgG labeled lymphocytes was higher in the minimum vaccination groups. A significant treatment by time inter action in CD4, IgG, and IgM labeled cells was observed. This interacti on, however, was not significant at any point in time for CD4 and IgG labeled cells. The percentage of lymphocytes expressing surface IgM wa s significantly higher in the minimum vaccination groups at 10 and 14 weeks of age. No significant differences were detected in humoral immu nity between the maximum and minimum groups of each litter. Results of this study indicate that maximum vaccination schedules do not appear to be more effective or more immunosuppressive than minimum vaccinatio n schedules.