Serological Responses of Brucella Melitensis Vaccine Rev-۱ Strain in Lambs

BACKGROUND AND OBJECTIVESBrucellosis is a common infectious disease between humans and livestock and is still a major problem in most parts of the world. Brucella melitensis Rev-۱ vaccine is one of the effective vaccines for preventing and controlling brucellosis in young lambs. In this study, serological responses of Razi institute's Brucella Rev-۱ vaccine and its comparison with the commercial Spanish vaccine (CZV) were evaluated .MATERIALS AND METHODS۱۲ female sheep (۵-۸ months old) free of brucellosis were divided into ۳ groups of ۴. One group was injected as a control by injection of physiological serum and the other two groups with Brucella melitensis vaccine made by Razi Institute and Spanish Brucella melitensis (CZV) vaccine, respectively. Blood samples and sera were collected from all groups in ۰, ۲, ۴ and ۶ weeks after vaccination. All animals with brucellosis strain ۱۶M were challenged after six weeks of vaccination. Then, all animal serum samples were evaluated by Rose Bengal (RBPT), Wright (SAT) and ۲ME (۲-Mercaptoethanol) and ELISA assay.RESULTS AND DISCUSSIONThe results showed that the animals in the control group were serologically negative in all experiments during the ۶ weeks before the challenge experiment. The first positive serologic reaction based on RBPT, SAT and ۲ME test results was recorded in the second week in both groups and was positive up to ۶ weeks after vaccination. In the fourth week, agglutination titer increased in both groups vaccinated with domestic or commercial CZV vaccine and there was no significant difference between both groups with serologic results of SAT and ۲ME (P>۰.۰۵). The results of the challenge experiment showed that all vaccinated and control groups showed positive serological responses at weeks ۲, ۴ and ۶ with increased agglutination titer.CONCLUSIONThe positive serological reactions of the vaccine group (made by Razi Institute) were similar to the positive reactions in the commercial vaccine (CZV) group. It seems that due to similar results of two vaccines in stimulating the humoral immune system of young lambs affect the function of CD۴ Th۲ type lymphocytes and are currently under investigation.

کلیدواژه ها:

Vaccine ، Brucella melitensis ، Serology.