Immune Response of Chickens to Six Strains of Newcastle Disease Virus as Measured by Hemagglutination-Inhibition Test

Abstract

SUMMARY Six strains of beta-propiolactone-inactivated Newcastle disease virus were compared for their immunogenicity in chickens. Texas GB, Kansas-Manhattan, and B1-Hitchner produced significantly higher HI antibody than NJ-LaSota, Mass-MK-107, and California 11914 strains of NDV, with each group performing about the same. Hanson et al. (3), in a comparison of the immunogenicity of five strains of Newcastle disease virus (NDV) as formalized antigens, showed that chickens immunized with Manhattan-Kansas and Roakin-NJ were more resistant to challenge than chickens receiving GB-Texas, RO and B1 strains. Sullivan et al. (4), using beta-propiolactone-killed preparations of three strains of NDV, demonstrated that a single injection of GB-Texas afforded better protection than a single injection of Roakin or Manhattan-Kansas. After a booster injection, however, chickens receiving any of the three strains showed essentially the same resistance to challenge. A study was made to compare the immune response of chickens to 6 strains of beta-propiolactone-inactivated NDV and to determine whether strain virulence could be correlated with antigenicity. To circumvent the difficulties encountered by other investigators, the quantity of antigen in each strain of virus used for vaccination was standardized and the serum from individual birds was tested for antibody. The hemagglutination-inhibition (HI) antibody titers were then compared both within and between strains of NDV to determine their significance.