Laboratory of Avian Immunology and Vaccines, Institute of Agrobiotechnology and Molecular Biology, INTA-CONICET, Buenos Aires, Argentina.
Department of Pathology, Faculty of Veterinary Sciences, University of Buenos Aires, Buenos Aires, Argentina.
Poult Sci. 2023 Dec;102(12):103129. doi: 10.1016/j.psj.2023.103129. Epub 2023 Sep 20.
Immunosuppressive diseases cause great losses in the poultry industry, increasing the susceptibility to infections by other pathogens and promoting a suboptimal response to vaccination. Among them, infectious bursal disease virus (IBDV) arises as one of the most important around the world. IBDV infects immature B lymphocytes, affecting the immune status of birds and facilitating infections by other pathogens such as avian infectious bronchitis virus (IBV). Although it has been reported that the interaction between these viruses increases IBV clinical signs, there are no actual studies about the interaction between regional circulating isolates that validate this statement. In this context, the objective of our work was to evaluate the effect of the interaction between local isolates of IBDV (belonging to genogroup 4) and IBV (lineage GI-16) in chickens. Thus, specific pathogen-free chickens were orally inoculated with IBDV genogroup (G) 4 or with PBS at 5 d of age. At 14-days postinoculation (dpi) the animals were intratracheally inoculated with a GI-16 IBV or with PBS. At multiple time points, groups of birds were euthanized and different parameters such as histological damage, viral load, lymphocyte populations and specific antibodies were evaluated. The success of IBDV infection was confirmed by the severity of bursal atrophy, viral detection, and presence of anti-IBDV antibodies. In IBV-infected animals, the presence of viral genome was detected in both kidney and bursa. The coinfected animals showed higher degree of lymphocyte infiltration in kidney, higher rate of animals with IBV viral genome in bursa at 28 dpi, and a clear decrease in antibody response against IBV at 28, 35, and 40 dpi. The results indicate that the infection with the local isolate of IBDV affects the immune status of the chickens, causing major severe damage, in response to IBV infection, which could consequently severely affect the local poultry industry.
免疫抑制性疾病给家禽业造成了巨大损失，增加了家禽对其他病原体感染的易感性，并导致对疫苗接种的反应不佳。其中，传染性法氏囊病病毒（IBDV）是全球最重要的病原体之一。IBDV 感染未成熟的 B 淋巴细胞，影响鸟类的免疫状态，并促进其他病原体（如禽传染性支气管炎病毒（IBV））的感染。尽管已经报道了这些病毒之间的相互作用会增加 IBV 的临床症状，但没有实际研究证实区域循环分离株之间的相互作用。在这种情况下，我们的工作目的是评估当地分离株的 IBDV（属于基因 4 组）和 IBV（GI-16 谱系）之间相互作用对鸡的影响。因此，在 5 日龄时，无特定病原体鸡通过口服接种 IBDV 基因 4 组或 PBS。在接种后 14 天（dpi），通过气管内接种 GI-16 IBV 或 PBS 对动物进行接种。在多个时间点，对鸡群进行安乐死，并评估组织病理学损伤、病毒载量、淋巴细胞群和特异性抗体等不同参数。通过法氏囊萎缩的严重程度、病毒检测和抗 IBDV 抗体的存在来确认 IBDV 感染的成功。在感染 IBV 的动物中，在肾脏和法氏囊中均检测到病毒基因组的存在。在共感染动物中，肾脏中的淋巴细胞浸润程度更高，在 28 dpi 时法氏囊中具有 IBV 病毒基因组的动物比例更高，并且在 28、35 和 40 dpi 时针对 IBV 的抗体反应明显下降。结果表明，当地分离株 IBDV 的感染会影响鸡的免疫状态，导致对 IBV 感染的严重反应，这可能会严重影响当地家禽业。
