Fadly A M, Nazerian K
U.S. Department of Agriculture, Regional Poultry Research Laboratory, East Lansing, Michigan 48823.
Avian Dis. 1989 Oct-Dec;33(4):778-86.
The effect of maternal antibody (MAB) to hemorrhagic enteritis (HE) on the response of turkeys to infection with virulent and avirulent strains of HE virus (HEV) was examined. The influence of age at exposure and treatment with HEV antibody on development of clinical HE also was studied. MAB protected poults from clinical HE for up to 6 weeks of age. MAB also interfered with vaccination against the disease for at least 5 weeks after hatching, as indicated by absence of HEV antigen in spleens and by poor seroconversion at 6 days and at 3 weeks post-vaccination, respectively. The incidence of clinical HE in MAB-negative poults was significantly higher in poults inoculated with virus at 15 days of age or older than in poults inoculated at 1-13 days of age. Further, MAB-negative poults embryonally inoculated with virulent or avirulent strains of HEV did not develop disease; these poults developed antibody and resisted challenge with virulent virus at 6 weeks of age. Poults treated with HE antibody within 1 hour of challenge or at 1, 3, or 5 weeks before challenge with virulent virus were protected against lesions and mortality induced by HEV. These results suggest that MAB may influence susceptibility of turkeys to infection with HEV for at least 5 to 6 weeks after hatching, unlike the case with most other viral infections of poultry. The results confirm that early age resistance to clinical HE is independent of MAB and suggest that such resistance persists for up to 13 days of age. The data also suggest that turkeys lacking MAB can be immunized against HE by embryo vaccination.
研究了母源抗体（MAB）对出血性肠炎（HE）的作用，以及火鸡对强毒株和无毒株HE病毒（HEV）感染的反应。还研究了暴露时的年龄和HEV抗体处理对临床HE发展的影响。MAB可保护雏火鸡至6周龄不发生临床HE。MAB还干扰雏火鸡出壳后至少5周的疫苗接种，这分别通过脾脏中缺乏HEV抗原以及接种疫苗后6天和3周时血清转化率低来表明。15日龄及以上接种病毒的MAB阴性雏火鸡临床HE的发病率显著高于1 - 13日龄接种的雏火鸡。此外，胚胎接种强毒株或无毒株HEV的MAB阴性雏火鸡未发病；这些雏火鸡产生了抗体，并在6周龄时抵抗了强毒株病毒的攻击。在感染强毒株病毒前1小时内或在感染前1、3或5周用HE抗体处理的雏火鸡，可免受HEV诱导的病变和死亡。这些结果表明，与大多数其他家禽病毒感染不同，MAB可能在雏火鸡出壳后至少5至6周影响其对HEV感染的易感性。结果证实，幼雏对临床HE的抵抗力与MAB无关，并表明这种抵抗力可持续至13日龄。数据还表明，缺乏MAB的火鸡可通过胚胎接种进行HE免疫。
