Central Veterinary Institute of Wageningen UR, The Netherlands, Lelystad, The Netherlands.
Avian Pathol. 2011 Feb;40(1):87-92. doi: 10.1080/03079457.2010.541226.
After avian influenza (AI) vaccination, hens will produce progeny chickens with maternally derived AI-specific antibodies. In the present study we examined the effect of maternal immunity in young chickens on the protection against highly pathogenic AI H5N1 virus infection and on the effectiveness of AI vaccination. The mean haemagglutination inhibition antibody titre in sera of 14-day-old progeny chickens was approximately eight-fold lower than the mean titre in sera of vaccinated hens. After H5N1 infection at the age of 14 days, chickens with maternal antibody titres lived a few days longer than control chickens. However, only a low proportion of chickens with maternal immunity survived challenge with H5N1. In most progeny chickens with maternal immunity, high virus titres (>10(4) median embryo infective dose) were present in the trachea during the first 4 days after H5N1 infection. In the cloaca, only low virus titres were present in most chickens. In 14-day-old progeny chickens with maternal immunity, the induction of antibody titres by vaccination was severely inhibited, with only a few chickens showing responses similar to the control chickens. It is concluded that high maternal antibody titres are required for clinical protection and reduction of virus titres after infection of chickens, whereas low antibody titres already interfere with vaccine efficacy.
禽流感（AI）疫苗接种后，母鸡将产生具有母体衍生的 AI 特异性抗体的后代鸡。在本研究中，我们研究了母源免疫对幼鸡的保护作用，以抵抗高致病性 AI H5N1 病毒感染，并评估了 AI 疫苗接种的效果。14 日龄后代鸡血清中的平均血凝抑制抗体滴度比接种母鸡血清中的平均滴度低约 8 倍。14 日龄感染 H5N1 后，具有母源抗体滴度的鸡比对照鸡多活几天。然而，只有少数具有母源免疫力的鸡能够抵抗 H5N1 的挑战。在大多数具有母源免疫力的后代鸡中，在 H5N1 感染后的头 4 天，气管中的病毒滴度很高（>10（4）中位胚胎感染剂量）。在大多数鸡中，泄殖腔中的病毒滴度较低。在具有母源免疫力的 14 日龄后代鸡中，疫苗接种诱导的抗体滴度受到严重抑制，只有少数鸡表现出与对照鸡相似的反应。结论是，高母源抗体滴度是临床保护和感染后鸡病毒滴度降低所必需的，而低抗体滴度已经干扰了疫苗的效果。
