Winterfield R W, Hoerr F J, Fadly A M
Poult Sci. 1978 Mar;57(2):386-91. doi: 10.3382/ps.0570386.
An immunosuppressive effect was demonstrated in chickens which were infected with infectious bursal disease virus (IBDV) early in life and prior to or shortly after vaccination with infectious bronchitis virus (IBV). This effect was evident by an increased susceptibility to respiratory tract infection with IBV and reduced virus-serum neutralizing antibody levels. Chickens which were hatched from dams susceptible to infectious bursal disease (IBD) were less responsive to IBV immunization attempts, if exposed to IBDV, than were those individuals hatched from IBD immune dams. However, in some cases, chickens from IBD immune dams were also more susceptible to IBV challenge when they had been exposed to IBDV and when compared to birds unexposed to IBDV but vaccinated against IB. An effect of cyclophosphamide on the bursa of Fabricius also had an immunosuppressive action on IBV immunity which was similar to the results from IBDV exposure. The data engendered from these trials may explain the unsatisfactory immunity sometimes observed under field conditions when broilers and replacement pullets are vaccinated at an early age.
在生命早期感染传染性法氏囊病病毒（IBDV）且在接种传染性支气管炎病毒（IBV）之前或之后不久的鸡身上，表现出了免疫抑制作用。这种作用表现为对IBV呼吸道感染的易感性增加以及病毒血清中和抗体水平降低。如果暴露于IBDV，从易患传染性法氏囊病（IBD）的母鸡所孵出的鸡，与从IBD免疫的母鸡所孵出的个体相比，对IBV免疫接种的反应较弱。然而，在某些情况下，当暴露于IBDV时，与未暴露于IBDV但接种了IB疫苗的鸡相比，来自IBD免疫母鸡的鸡对IBV攻击也更易感。环磷酰胺对法氏囊的作用也对IBV免疫有免疫抑制作用，这与暴露于IBDV的结果相似。这些试验产生的数据可能解释了在野外条件下有时观察到的、当肉鸡和后备蛋鸡在幼龄时接种疫苗时免疫效果不佳的情况。
