[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was...[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was immunized with H120 live vaccine. The group A2 was first immunized with H120 live vaccine and later boosted with ND-IB-EDS trivalent inactivated vaccine. The group B1 was used as unimmunized chal- lenge control. The group B2 was kept as unimmunized unchallenged control. The blood samples were taken prior and post-vaccination at intervals and HI tests were conducted. At the laying peak, the group A1, A2 and B1 were challenged with IBV M4t virulent strain. The clinical features and egg production of layers were monitored and recorded. [Result] After 30 d post vaccination with H120 live vaccine, the HI titer reached 4.45 log2; after 30 days boosting with ND-IB-EDS trivalent inactivated vaccine, the HI titer reached to 7.35 log2. Before challenge, HI antibody titer in group A1, A2, B1 and B2 were respectively 4.24 log2, 7.40 Iog2, 2.10 log2 and 2.10 log2. After challenge, chickens in unimmunized challenge control group B1 showed respiratory symptoms, egg production dropped by 30.9%, and they produced more soft-shelled, no-shelled or abnormal eggs. In the group A1, some chickens had light respiratory symptoms and egg production dropped by 11.7%. In the group A2, the egg production of all chickens was as normal as the group B2. [ Conclusion] When the HI titer was over 6 log2, challenge by virulent virus had no impact on egg produc- tion; when the HI titer was 5 log2, 4 log2 and less 3 log2, egg production dropped by 6.0%, 11.3% and 29.6%, respectively. Thus, the HI anti- body level in chickens has close correlation with protection against IBV challenge.展开更多
Aluminum hydroxide sol （consisting of aluminum hydroxide nano-particles） prepared by a hydrothermal method was used as nano-aluminum adjuvant adsorbed the inactived Newcastle disease virus （NDV）. The zeta potentia...Aluminum hydroxide sol （consisting of aluminum hydroxide nano-particles） prepared by a hydrothermal method was used as nano-aluminum adjuvant adsorbed the inactived Newcastle disease virus （NDV）. The zeta potential of aluminum hydroxide colloidal particles,the inactivated NDV and the nano-aluminum adjuvant NDV are ＋48.16 mV,？13.8 mV and ＋39.97 mV,respec-tively. The nano-aluminum adjuvant vaccine was transparent and stable without precipitate,whereas the conventional aluminum ad-juvant vaccine was turbid and a white precipitate was visible soon. The hemagglutination inhibition （HI） titers of the nano-aluminum adjuvant group were generally higher than those of the conventional aluminum group except the titer on day 29. The results show that the nano-aluminum adjuvant has better stability and higher levels of antibodies for a longer time than the conventional aluminum adjuvant.展开更多
文摘[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was immunized with H120 live vaccine. The group A2 was first immunized with H120 live vaccine and later boosted with ND-IB-EDS trivalent inactivated vaccine. The group B1 was used as unimmunized chal- lenge control. The group B2 was kept as unimmunized unchallenged control. The blood samples were taken prior and post-vaccination at intervals and HI tests were conducted. At the laying peak, the group A1, A2 and B1 were challenged with IBV M4t virulent strain. The clinical features and egg production of layers were monitored and recorded. [Result] After 30 d post vaccination with H120 live vaccine, the HI titer reached 4.45 log2; after 30 days boosting with ND-IB-EDS trivalent inactivated vaccine, the HI titer reached to 7.35 log2. Before challenge, HI antibody titer in group A1, A2, B1 and B2 were respectively 4.24 log2, 7.40 Iog2, 2.10 log2 and 2.10 log2. After challenge, chickens in unimmunized challenge control group B1 showed respiratory symptoms, egg production dropped by 30.9%, and they produced more soft-shelled, no-shelled or abnormal eggs. In the group A1, some chickens had light respiratory symptoms and egg production dropped by 11.7%. In the group A2, the egg production of all chickens was as normal as the group B2. [ Conclusion] When the HI titer was over 6 log2, challenge by virulent virus had no impact on egg produc- tion; when the HI titer was 5 log2, 4 log2 and less 3 log2, egg production dropped by 6.0%, 11.3% and 29.6%, respectively. Thus, the HI anti- body level in chickens has close correlation with protection against IBV challenge.
基金Supported by the National Science and Technology Supporting Program in the Eleventh Five-Year Plan of China (2006BAD06A08)
文摘Aluminum hydroxide sol （consisting of aluminum hydroxide nano-particles） prepared by a hydrothermal method was used as nano-aluminum adjuvant adsorbed the inactived Newcastle disease virus （NDV）. The zeta potential of aluminum hydroxide colloidal particles,the inactivated NDV and the nano-aluminum adjuvant NDV are ＋48.16 mV,？13.8 mV and ＋39.97 mV,respec-tively. The nano-aluminum adjuvant vaccine was transparent and stable without precipitate,whereas the conventional aluminum ad-juvant vaccine was turbid and a white precipitate was visible soon. The hemagglutination inhibition （HI） titers of the nano-aluminum adjuvant group were generally higher than those of the conventional aluminum group except the titer on day 29. The results show that the nano-aluminum adjuvant has better stability and higher levels of antibodies for a longer time than the conventional aluminum adjuvant.
