关键词: 免疫增强剂, 新城疫-传染性法氏囊二联灭活苗, 新城疫-H9亚型禽流感二联灭活苗, 抗体效价

Abstract:

In order investigate the efficacy of immunopotentiator (VA5) on bivalent vaccine in chickens, the antibody levels or the challenge protection efficacy were evaluated after the specific pathogen free chickens (SPF) and commercial layers immunized with the bivalent inactivated ND-IBD vaccines with or without VA5, respectively. The other detection way was only taking SPF chicken injected by bivalent ND-AI vaccines with or without VA5, in contrast with bivalent vaccine without VA5 groups. HI antibody level against ND antigen was achieved to 6 log2 one week early in both ND contained bivalent vaccines with VA5 groups. And HI antibody level against H9 AI antigen reached to 7 log2 one week advanced in ND-AI vaccine with VA5 group. Antibody titers of agar gel precipitation titer and serum-virus neutralization against IBD antigen were qualified one week in advance than in ND-IBD vaccine with VA5 group, and continuously high antibody titer against ND, H9 AI and IBD antigen were retained during the detection periods. Similar to the antibody level results, groups of chickens injection by bivalent vaccines with VA5 could fully protect against virulent-ND or -IBD viruses challenge based on clinical signs and (or) bursa gross lesions, and no virus shedding post H9 AI variants infection. The protective efficacy of adjuvant bivalent vaccine groups was higher than those of bivalent vaccine without VA5 groups in term of the results of the three types viruses challenge. In summary, the immune efficacy of both ND-IBD and ND-AI bivalent vaccines was improved by VA5 immunopotentiators, which had shown great application prospects in this field.

Key words: immunopotentiator, bivalent inactivated ND-IBD vaccines, bivalent inactivated ND-H9 subtype avian influenza vaccines, antibody titer