Hinshaw V S, Sheerar M G, Larsen D
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison 53706.
Avian Dis. 1990 Jan-Mar;34(1):80-6.
To examine the specificity of the antibody response to the influenza hemagglutinin and the generation of antigenic variants, chickens were immunized against the highly virulent H5 virus A/Ty/Ont/7732/66 (H5N9) and then challenged with a lethal dose of the virus. The antibody responses of these chickens to the hemagglutinin (HA) were examined with an enzyme-linked immunosorbent assay (ELISA) in which their sera were titrated for the ability to block the binding of monoclonal antibodies (MAbs) to five distinct neutralizing epitopes on the viral HA. Based on the ELISA results, a majority (5/6) of the chickens produced antibodies to three of the five neutralizing epitopes on the viral HA. After challenge, two of six immunized chickens shed virus and died; antigenic comparisons of isolates from these two chickens indicated the presence of an antigenic variant; i.e., there was a change in one neutralizing epitope on the HA of virus shed by one chicken. None of the chickens had produced antibodies to this particular epitope on the viral HA. Inoculation of chickens with this variant resulted in 100% mortality, demonstrating that a change in this particular epitope did not alter the virulence of the virus. These studies indicate that chickens immunized against highly virulent influenza viruses may excrete virulent variants following challenge with live virus.
为了检测针对流感血凝素的抗体反应特异性以及抗原变体的产生，用高致病性H5病毒A/Ty/Ont/7732/66（H5N9）对鸡进行免疫，然后用致死剂量的该病毒进行攻毒。用酶联免疫吸附测定（ELISA）检测这些鸡对血凝素（HA）的抗体反应，在该测定中，滴定它们的血清以检测其阻断单克隆抗体（MAb）与病毒HA上五个不同中和表位结合的能力。根据ELISA结果，大多数（5/6）鸡产生了针对病毒HA上五个中和表位中三个的抗体。攻毒后，六只免疫鸡中有两只排出病毒并死亡；对这两只鸡分离株的抗原比较表明存在抗原变体；即，其中一只鸡排出的病毒HA上一个中和表位发生了变化。没有一只鸡产生针对病毒HA上这个特定表位的抗体。用这种变体接种鸡导致100%的死亡率，表明这个特定表位的变化并未改变病毒的毒力。这些研究表明，用高致病性流感病毒免疫的鸡在用活病毒攻毒后可能排出有毒力的变体。
