Study on the fluctuation of serum antibodies of dairy goats immunized with different doses of Brucella S2 vaccine

Zhang Yating; Chen Lan; Chen Xindi; Wang Tengyu; Cao Tianyu; Yu Yu; Meng Xianran; Wang Wenlong

doi:10.20154/j.cnki.issn1672-9692.2025.01.003

Abstract：This study was conducted to investigate the change of serum antibodies in dairy goats immunized with different doses of Brucella S2 vaccine.26 dairy goats aged 5 months were randomly divided into two groups with 13 sheep in each group.The one-dose and two-dose groups received 1010 and 2.0×1010 CFU Brucella S2 vaccine orally,and blood samples were collected before and after immunization on days 3,5,7,15,21,30,60,90,120,150,180,210,240,respectively.Tiger Red plate agglutination test(RBPT),test tube agglutination test(SAT)and indirect enzyme-linked immunosorbent assay(iELISA)were used to monitor the changes of serum antibody positive rate of dairy goats.The results showed that the antibody began to be produced on the 7th day after oral immunization with double dose of S2 vaccine.The positive rates of RBPT,SAT and iELISA were 84.6%,84.6%and 92.3%on the 21th day,respectively.On the 90th day after immunization,most of the antibodies turned negative,and the positive rates of antibodies measured by RBPT,SAT and iELISA were 23.1%.After 210 days of immunization,the results of the three detection methods were negative.Experimental goats produced antibodies on 5th day after oral immunization with two-dose of Brucella S2 vaccine.On the 15th day after immunization,the antibody positive rate measured by SAT and iELISA reached the highest(92.3%),and on the 21st day after immunization,the antibody positive rate measured by RBPT reached the highest(92.3%).The positive rate of antibody decreased on the 30th day after immunization.On the 90th day after immunization,most of the antibodies turned negative,and the positive rates of antibodies measured by RBPT,SAT and iELISA were 15.4%,15.4%,and 23.1%,respectively.At 180 days after immunization,the antibody results of the three methods were negative.Studies have shown that the Brucella S2 vaccine can make dairy goats produce antibodies quickly after immunization and antibodies can be maintained for half a year,and there is no significant difference in the immune effect between one and two oral doses.