Ugwu Chidozie Clifford, Hair-Bejo Mohd, Nurulfiza Mat Isa, Omar Abdul Rahman, Ideris Aini
Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.
Department of Animal Science and Technology, Federal University of Technology, Owerri 460114, Imo State, Nigeria.
Vet World. 2022 Nov;15(11):2681-2692. doi: 10.14202/vetworld.2022.2681-2692. Epub 2022 Nov 26.
Fowl adenovirus (FAdV) 8b causes inclusion body hepatitis, resulting in major economic losses globally among chickens. The objectives were to inactivate FAdV 8b isolate propagated in chicken embryo liver (CEL) cells using a stirred tank bioreactor (UPM08136P5B1) and determine the humoral and cell-mediated immune response, efficacy, and virus shedding in broiler chickens.
The FAdV 8b isolate UPM08136P5B1 was inactivated using binary ethyleneimine, adjuvanted with Montanide 71VG, inoculated into day-old broiler chickens in a booster group (BG) and non-booster group (NBG), and challenged with a pathogenic FAdV 8b strain. Clinical signs, gross lesions, body weight (BW), liver: body weight ratio, FAdV antibody titer using enzyme-linked immunosorbent assay, and histopathological changes were recorded. The CD3+, CD4+, and CD8+ T-lymphocyte profiles of the liver, spleen, and thymus using flow cytometry, and viral load in liver and cloacal shedding using quantitative polymerase chain reaction were evaluated.
Chickens in the challenged control group (CCG) exhibited mild clinical signs, gross lesions, and histopathological changes, which were absent in the inoculated groups, and had lower BW and higher liver BW ratio than chickens in the unchallenged control group (UCG); BG and NBG on 35- and 42-days post-inoculation (DPI). Chickens in NBG and BG had higher antibodies than UCG on 7, 21, 35, and 42 DPI. The challenged BG and NBG produced higher antibodies than the CCG on 35 DPI. T-lymphocytes were higher among the inoculated groups than UCG in the liver, spleen, and thymus. Inoculated challenged groups recorded higher CD3+, CD4+, and CD8+ T-lymphocytes on 35 and 42 DPI than CCG. The challenged control group had a significantly higher viral load in the liver than challenged that in BG on 35 DPI and BG and NBG on 42 DPI. The challenged control group had significantly higher challenge FAdV shedding than challenged inoculated groups on 35 and NBG on 42 DPI.
UPM08136P5B1 was successfully inactivated and mixed with Montanide 71VG. The inactivated vaccine candidate that induced humoral and cellular immunity was effective, reduced FAdV load in the liver, and shedding in the cloaca, and could be useful against FAdV 8b infections in chickens.
禽腺病毒8b型（FAdV - 8b）可引起包涵体肝炎，在全球范围内给养鸡业造成重大经济损失。本研究旨在使用搅拌罐生物反应器（UPM08136P5B1）灭活在鸡胚肝（CEL）细胞中繁殖的FAdV - 8b分离株，并确定其在肉鸡中的体液免疫和细胞介导免疫反应、效力及病毒排泄情况。
使用双乙烯亚胺对FAdV - 8b分离株UPM08136P5B1进行灭活，佐以Montanide 71VG，接种于加强免疫组（BG）和非加强免疫组（NBG）的1日龄肉鸡，并使用致病性FAdV - 8b毒株进行攻毒。记录临床症状、大体病变、体重（BW）、肝重与体重比、采用酶联免疫吸附测定法检测的FAdV抗体效价以及组织病理学变化。使用流式细胞术检测肝脏、脾脏和胸腺中的CD3 +、CD4 +和CD8 + T淋巴细胞谱，并使用定量聚合酶链反应评估肝脏中的病毒载量和泄殖腔病毒排泄情况。
攻毒对照组（CCG）的鸡表现出轻微的临床症状、大体病变和组织病理学变化，接种组未出现这些情况，且与未攻毒对照组（UCG）相比，CCG的鸡体重较低，肝重与体重比更高；在接种后35天和42天，NBG和BG组的情况如此。在接种后7天、21天、35天和42天，NBG和BG组的鸡抗体水平高于UCG组。在接种后35天，攻毒的BG组和NBG组产生的抗体高于CCG组。接种组肝脏、脾脏和胸腺中的T淋巴细胞高于UCG组。在接种后35天和42天，接种攻毒组的CD3 +、CD4 +和CD8 + T淋巴细胞高于CCG组。在接种后35天，攻毒对照组肝脏中的病毒载量显著高于攻毒BG组，在接种后42天，高于攻毒BG组和NBG组。在接种后35天，攻毒对照组的攻毒FAdV排泄量显著高于攻毒接种组，在接种后42天，高于攻毒NBG组。
UPM08136P5B1成功灭活并与Montanide 71VG混合。诱导体液免疫和细胞免疫的灭活候选疫苗有效，可降低肝脏中的FAdV载量和泄殖腔中的病毒排泄，可能对预防鸡FAdV - 8b感染有用。
