H9亚型禽流感病毒流行毒株交叉免疫攻毒保护试验

采用1998-2009年在河北、河南及山东分离的3株禽流感H9亚型流行毒株,分别制备灭活疫苗,免疫SPF鸡,免疫后21d,采血测定HI抗体,然后用从上述3个地区及北京分离的共5株禽流感H9亚型流行毒株进行攻击,观察不同时期及地点分离的H9亚型流行毒株的交叉免疫攻毒保护效果。结果显示,用不同时期及地点的3个分离毒株所制备出的灭活疫苗免疫鸡后,各免疫组试验鸡H9亚型禽流感的HI抗体效价均明显上升,不同毒株灭活疫苗所诱导产生的HI抗体效价存在着不同程度的差异,用同源毒株作为抗原测定免疫组鸡的血清样品,可获得较高的HI抗体效价。攻毒试验结果证明,对不同时期及地点分离的禽流感H9亚型流行毒株间产生了较好的交叉保护力。用1998年分离的WD98株制备出的灭活疫苗对目前的流行毒株仍具有较好的保护效力。

Study on Immunization and Cross-protection against Circulating H9 Subtype Avian Influenza Virus Isolates

Inactivated vaccines were prepared with three H9 subtype AIV isolated from Hebei, Henan and Shandong between 1998-2009. SPF chickens were vaccinated and 21 days later blood samples were collected for HI test. Five field isolates from Hebei, Henan, Shandong and Beijing were used to infect immunized chickens to examine the protectivity of the candidate vaccines made with above isolates. The HI test results showed that HI antibody levels against the H9 antigens triggered by the three candidate vaccines were apparently increased. Although there was certain degree of differences at the antibody titers raised with different vaccines, using homologous virus as antigen resulted in higher HI titers. The challenge experiments showed that H9 subtype AIV strains isolated at different time and places produced sound cross-protection. The study also demonstrated that the inactivated vaccine prepared with 1998 field isolate WD98 offered fairly good protection against current circulating H9 subtype AIVs.