What is a good or protective titer?
A minimum protective antibody titer has not been established for Clostridium perfringens type A toxoid. A hemolysis inhibition test, however, was developed to test the antibody response of pullets following vaccination. Antibody titers were evaluated in SPF White Leghorn pullets following immunization with Clostridium perfringens type A toxoid vaccine administered subcutaneously. The pullets were vaccinated at 15 weeks of age with 0.5 mL of the vaccine and a booster dose was administered 4 weeks later. Blood samples were collected 6 weeks after the booster. Serum from each individual bird was evaluated for antibody titer by the hemolysis inhibition assay and ranged from 512 to 8,192, with a GMT of 1,290. In contrast, serum samples from control birds showed a GMT of ≤ 2, with a maximum value of 4. The antibody titer in eggs collected at 25 weeks of age from the White Leghorn layers were also evaluated and showed a pooled value of 512, whereas eggs from control birds showed a pooled valu
