S. C. YANG', W. C. HWANG', M. S. CHO', L. F. LIN' M. C. LIU',S.C.CHEN,Y.C. PERNG,F.T.HONG I. P.CHEN
Eight-weeks-old chicks immunized with various doses of inactivated or live attenu-ated newcastle (ND) virus vaccines showed different responses in the hemoagglutination inhibition antibody CHI) and serum neutralization antibody (SN) productions in 14 days after vaccination. The tested chicks which got a low HJ antibody after vaccination showed low SN antibody levels. After the chicks were challenged with the virulent virus, both the HJ antibody and SN antibody production were presented with reciprocal relations to the antibody levels before the challenge.
The survival rate of the immunized chicks possessing the HI antibody and SN antibody level ≦2 was 48-67% and 23.1 %, and≦1 : 4 was 80% and 93% respectively. It is concluded that the chicks immunized with the ND virus vaccine induced the HI antibody orer 1 : 16 may get good protection against this disease.