Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
Southeast Poultry Research Laboratory, Agricultural Research Service, USDA, Athens, GA, USA.
BMC Vet Res. 2019 Sep 4;15(1):317. doi: 10.1186/s12917-019-2053-z.
Newcastle disease (ND), which is caused by infections of poultry species with virulent strains of Avian orthoavulavirus-1, also known as avian paramyxovirus 1 (APMV-1), and formerly known as Newcastle disease virus (NDV), may cause neurological signs and encephalitis. Neurological signs are often the only clinical signs observed in birds infected with neurotropic strains of NDV. Experimental infections have shown that the replication of virulent NDV (vNDV) strains is in the brain parenchyma and is possibly confined to neurons and ependymal cells. However, little information is available on the ability of vNDV strains to infect subset of glial cells (astrocytes, oligodendrocytes, and microglia). The objective of this study was to evaluate the ability of NDV strains of different levels of virulence to infect a subset of glial cells both in vitro and in vivo. Thus, neurons, astrocytes and oligodendrocytes from the brains of day-old White Leghorn chickens were harvested, cultured, and infected with both non-virulent (LaSota) and virulent, neurotropic (TxGB) NDV strains. To confirm these findings in vivo, the tropism of three vNDV strains with varying pathotypes (SA60 [viscerotropic], TxGB [neurotropic], and Tx450 [mesogenic]) was assessed in archived formalin-fixed material from day-old chicks inoculated intracerebrally.
Double immunofluorescence for NDV nucleoprotein and cellular markers showed that both strains infected at least 20% of each of the cell types (neurons, astrocytes, and oligodendrocytes). At 24 h post-inoculation, TxGB replicated significantly more than LaSota. Double immunofluorescence (DIFA) with markers for neurons, astrocytes, microglia, and NDV nucleoprotein detected the three strains in all three cell types at similar levels.
These data indicate that similar to other paramyxoviruses, neurons and glial cells (astrocytes, oligodendrocytes, and microglia) are susceptible to vNDV infection, and suggest that factors other than cellular tropism are likely the major determinant of the neurotropic phenotype.
由禽正黏病毒 1 型（也称为禽副黏病毒 1 型，APMV-1）强毒株引起的禽新城疫（ND）也会导致神经症状和脑炎。神经症状通常是感染神经过敏型 NDV 毒株的鸟类中观察到的唯一临床症状。实验感染表明，强毒 NDV（vNDV）株的复制位于脑实质中，可能局限于神经元和室管膜细胞。然而，关于 vNDV 株感染神经胶质细胞亚群（星形胶质细胞、少突胶质细胞和小胶质细胞）的能力的信息很少。本研究的目的是评估不同毒力水平的 NDV 株在体外和体内感染神经胶质细胞亚群的能力。因此，从 1 日龄白来航鸡的大脑中收获神经元、星形胶质细胞和少突胶质细胞，进行培养，并感染非致弱的（LaSota）和致弱的、神经过敏的（TxGB）NDV 株。为了在体内证实这些发现，评估了 3 种具有不同病理型的 vNDV 株（SA60[内脏型]、TxGB[神经型]和 Tx450[中体型]）在接种脑内的 1 日龄雏鸡存档的福尔马林固定材料中的趋向性。
NDV 核蛋白和细胞标志物的双重免疫荧光显示，两种毒株均感染了至少 20%的每种细胞类型（神经元、星形胶质细胞和少突胶质细胞）。接种后 24 小时，TxGB 的复制量明显多于 LaSota。神经元、星形胶质细胞、小胶质细胞和 NDV 核蛋白的双重免疫荧光（DIFA）检测到三种株在所有三种细胞类型中以相似的水平存在。
这些数据表明，与其他副黏病毒一样，神经元和神经胶质细胞（星形胶质细胞、少突胶质细胞和小胶质细胞）易感染 vNDV，并且表明除细胞趋向性以外的因素可能是神经过敏表型的主要决定因素。
