Research and Development Laboratories, FARVET, Carretera Panamericana Sur No 766 Km 198.5, Ica, Peru.
Vet Res. 2020 Sep 25;51(1):123. doi: 10.1186/s13567-020-00840-7.
Infectious coryza (IC), an upper respiratory tract disease affecting chickens, is caused by Avibacterium paragallinarum. The clinical manifestations of IC include nasal discharge, facial swelling, and lacrimation. This acute disease results in high morbidity and low mortality, while the course of the disease is prolonged and mortality rates are increased in cases with secondary infections. Studies regarding the immune response in infected chickens are scarce, and the local immune response is the focal point of investigation. However, a large body of work has demonstrated that severe infections can impact the systemic immune response. The objective of this study was to evaluate the systemic effects of Avibacterium paragallinarum (serovar B-1) infection on immune cells in specific pathogen-free (SPF) chickens. The current study revealed the presence of a transient circulating monocyte population endowed with high phagocytic ability and clear downregulation of major histocompatibility complex class II (MHC-II) surface expression. In human and mouse studies, this monocyte population (identified as tolerant monocytes) has been correlated with a dysfunctional immune response, increasing the risk of secondary infections and mortality. Consistent with this dysfunctional immune response, we demonstrate that B cells from infected chickens produced fewer antibodies than those from control chickens. Moreover, T cells isolated from the peripheral blood of infected chickens had a lower ability to proliferate in response to concanavalin A than those isolated from control chickens. These findings could be related to the severe clinical signs observed in complicated IC caused by the presence of secondary infections.
传染性鼻炎（IC）是一种影响鸡的上呼吸道疾病，由鹦鹉热衣原体引起。IC 的临床症状包括鼻分泌物、面部肿胀和流泪。这种急性疾病的发病率高，死亡率低，但在继发感染的情况下，病程延长，死亡率增加。关于感染鸡的免疫反应的研究很少，局部免疫反应是研究的重点。然而，大量研究表明，严重的感染会影响全身免疫反应。本研究旨在评估鹦鹉热衣原体（B-1 血清型）感染对特定无病原体（SPF）鸡免疫细胞的全身影响。本研究揭示了存在短暂循环单核细胞群体，具有高吞噬能力和主要组织相容性复合体 II（MHC-II）表面表达的明显下调。在人类和小鼠研究中，这种单核细胞群体（鉴定为耐受单核细胞）与功能失调的免疫反应相关，增加了继发感染和死亡率的风险。与这种功能失调的免疫反应一致，我们证明感染鸡的 B 细胞产生的抗体比对照鸡的少。此外，从感染鸡外周血分离的 T 细胞对刀豆蛋白 A 的增殖能力低于从对照鸡分离的 T 细胞。这些发现可能与继发感染引起的复杂 IC 中观察到的严重临床症状有关。
