IgM responses in chicken serum to live and inactivated infectious bronchitis virus vaccines.

Intramuscular (i.m.) administration of infectious bronchitis virus (IBV) oil-emulsion vaccine (OEV) to IBV-primed or unprimed chickens resulted in the production of zero or minimal concentrations of IBV-specific IgM in the serum, as measured by enzyme-linked immunosorbent assay of gel chromatography fractions. Live-attenuated infectious bronchitis (IB) vaccine given i.m. or by eyedrop stimulated the production of IBV-specific IgM in similar amounts following inoculation by both routes. These levels were comparable to those found in earlier studies following intranasal inoculation with a virulent strain of IBV and confirm that the detection of IBV-specific IgM is a valuable aid to the diagnosis of recent infection. As expected, administration of live-attenuated IB vaccines i.m. or by eyedrop protected the respiratory tract against challenge with virulent virus 24 days later; however, OEV given i.m. did not.     

鸡传染性支气管炎病毒对新城疫病毒的干扰作用观察

为观察鸡传染性支气管炎病毒（IBV）HN99株对新城疫病毒（NDV）增殖的干扰作用,该试验采用不同浓度的IBV标准株M41和地方株HN99与鸡新城疫病毒（NDV）分别按不同接种顺序同胚增殖,利用病毒血凝试验（HA）测定NDV的效价,观察IBV对NDV的干扰作用,从而为检测IBV地方株HN99提供方法,也为同胚增殖两种病毒提供一系列的数据参考。试验结果表明,鸡传染性支气管炎病毒地方株HN99对NDV的干扰作用与其浓度和接种顺序有关。     

Transmissibility of infectious bronchitis virus H120 vaccine strain among broilers under experimental conditions

The aim of this study was to quantify transmission of infectious bronchitis virus (IBV) H120 vaccine strain among broilers, and to assess whether birds that have been exposed to vaccine strain-shedding birds were protected against clinical signs after infection with a virulent strain of the same serotype. A transmission experiment and a replicate were carried out, each with six groups of commercial broilers. At day of hatch (n = 30) or at 15 days of age (n = 20), half of each group was inoculated with either IBV H120 vaccine (H120 group), virulent IBV M41 (M41 group), or were mock-infected, thereby contact-exposing the other half of each group. Nasal discharge was recorded, and antibody response and virus shedding were measured. To measure clinical protection, four weeks after inoculation all birds, in all groups, were challenged with IBV M41. The reproduction ratio (R; the average number of contact infections caused by one infectious bird) was determined to quantify virus transmission. All contact-exposed birds, except for one in an H120 group, became infected with either IBV H120 or IBV M41. Almost all birds contact-infected with IBV H120 or IBV M41 were subsequently protected against clinical signs after challenge with IBV M41. The lower limits of the 95% confidence interval (CI) of the R of IBV H120 vaccine, and of IBV M41, were significantly <1. For both IBV H120 and IBV M41, the 95% CI was [2.1-infinity] following inoculation at day of hatch and [1.8-infinity] after inoculation at 15 days of age. This finding demonstrates that IBV H120 vaccine is able to spread extensively among broilers. This implies that this vaccine strain might be able to become endemically present in the poultry population. It also implies that, even if not all birds received vaccine during spray application, due to the ability of the vaccine to spread in the flock, they will most likely be protected against clinical signs after a subsequent field virus infection.     

单抗免疫过氧化物酶技术检测鸡传染性支气管炎病毒

以抗鸡传染性支气管病毒（ＩＢＶ）核衣壳蛋白（Ｎ）的单抗株６ＤＨ８作为一抗,以辣根过氧化物酶标记的羊抗鼠ＩｇＧ作为二抗,建立了检测石蜡切片中ＩＢＶ抗原的单抗免疫过氧化物酶技术（Ｍｃ－ＩＰ）,并对人工攻毒鸡及临床ＩＢＶ感染疑似鸡进行了检测。在ＩＢＶＭ４１株人工攻毒鸡,用该技术于１～１２ｄ从气管、２～７ｄ从肾脏可以检测到ＩＢＶ抗原,阳性染色集中于气管粘膜上皮细胞及肾小管上皮细胞胞浆;临床疑为ＩＢＶ感染的病鸡,以Ｍｃ－ＩＰ技术和单抗免疫荧光试验（Ｍｃ－ＩＦＡ）同时进行检测,结果阳性率分别为９０．３％及８３．９％。     

Detection of avian infectious bronchitis viral infection using in situ hybridization and recombinant DNA

A recombinant DNA probe with specificity for the 3' end of genomic RNA from the Ark 99 strain of infectious bronchitis virus (IBV) was found to hybridize with extracted RNA of three strains with the Ark serotype, as well as the Mass41, Holl52, Gray, JMK, Conn, Fla and SE17 strains of IBV. Viral infection was detected in the cytoplasm of chicken embryo kidney cells inoculated with Mass41, Ark99, SE17 or two recent field isolates of IBV using in situ cytohybridization and a biotinylated probe. In vivo infections were detected in individual cells of tracheas and lungs 2,4, and 6 days after inoculation of chicks with Mass41 and Ark99. In situ hybridization of Ark99 infected tissue sections using 32P-dATP labelled probe indicated that more viral replication was present in the trachea on day 4 than either days 2 or 6; whereas more viral RNA was found in the lungs on day 6 than days 2 or 4 after inoculation.     

鸡肾型IBV的分离及其N基因的克隆与测序

通过病毒形态学观察、血凝试验、病毒干扰实验、动物回归实验等分离鉴定了1株鸡肾型传染性支气管炎病毒.利用RT-PCR技术对分离毒株的N基因进行了扩增,经克隆、序列测定和分析,证实分离株为肾型IBV.     

Infectious bronchitis virus nucleoprotein specific CTL response is generated prior to serum IgG

Infectious bronchitis (IB) is an acute and highly contagious viral respiratory disease of chickens. To understand the kinetics and relationships between the humoral (Ab) and antigen specific T cell immunity as well as pathological changes during infectious bronchitis virus (IBV) infection and immunization, one-week-old SPF chickens were vaccinated with live IBV H52 strain and challenged with IBV M41 15 days post primary infection. Chickens were sacrificed every 3 days to monitor antigen specific serum IgG and IBV nucleoprotein-specific immune responses using a chicken MHC I tetramer developed in our laboratory. The results demonstrated that T cell responses developed more rapidly than the humoral (Ab) immune response after vaccination with H52. However, serum IgG dramatically increased after M41 challenge. Chickens from the control, non-vaccinated group developed severe respiratory symptoms and demonstrated significant pathological changes in lung, kidney and bursa of Fabricius post challenge with M41. However, chickens vaccinated with H52 did not demonstrate clinical signs or histological changes post challenge with M41. These results indicated that the live IBV H52 inoculation effectively protected chickens from morbidity and pathological changes associated with IBV infection. These data facilitates the design of a new generation of IBV vaccine.     

Lymphoid organ and serologic responses of gnotobiotic and conventional chickens to infectious bronchitis virus and mixed infections of Mycoplasma synoviae and Escherichia coli

Lymphoid organ and serologic responses to infectious bronchitis virus (IBV) and mixed infections of Mycoplasma synoviae (MS) and Escherichia coli (EC) were evaluated in gnotobiotic and conventional chickens. Infectious bronchitis virus combined with MS and EC significantly depressed relative thymus weight and body weight in conventional chickens but not in gnotobiotic chickens. Lymphocyte concentration was greater in the thymic cortex of conventional chickens. Foci of lymphocyte infiltration in the liver and bursal-dependent lymphoid follicles of the spleen were larger in the chickens infected with IBV without apparent influence from the indigenous microflora. Infection with IBV enhanced the immune response to MS.     

Pathogenicity and antigenicity of a new variant of Korean nephropathogenic infectious bronchitis virus

Despite the existence of an active vaccination program, recently emerged strains of nephropathogenic infectious bronchitis virus (IBV) in Korea have caused significant economic losses in the poultry industry. In this study, we assessed the pathogenic and antigenic characteristics of a K-IIb type field strain of IBV that emerged in Korea since 2003, such as Kr/Q43/06. Specific pathogen free 1-week-old chickens exhibited severe respiratory symptoms (dyspnea) and nephropathogenic lesions (swollen kidneys with nephritis and urate deposits) following challenge with the recent IBV field strain. The antigenic relatedness (R value), based on a calculated virus neutralization index, of the K-IIb type field strain and K-IIa type strain KM91 (isolated in 1991) was 30%, which indicated that the recent strain, Kr/Q43/06, is a new variant that is antigenically distinct from strain KM91. This report is the first to document the emergence of a new antigenic variant of nephropathogenic IBV in chicken from Korea.     

An infectious bronchitis virus isolated from chickens experiencing a urolithiasis outbreak. I. In vitro characterization studies

An infectious bronchitis virus (IBV) strain isolated from commercial layers experiencing urolithiasis was 50-100 nm in size and possessed widely spaced, club-shaped surface projections. It was sensitive to lipid solvents and exhibited responses characteristic of IBV when exposed to heat, divalent cations, and trypsin. Reciprocal virus-neutralization tests demonstrated it to be closely related to Gray, JMK, Delaware 2868, and Delaware 2897 strains of IBV.     

Attenuation of avian infectious bronchitis virus by cold-adaptation.

Avian infectious bronchitis virus (IBV) Arkansas-type DPI strain was passaged 10 times in specific-pathogen-free (SPF) chicken embryos incubated at 28 C and 37 C. Virus grown at 28 C acquired cold-adapted (CA) and temperature-sensitive (TS) characteristics based on more-rapid growth at 28 C and a reduced ability to grown at 41 C, respectively, compared with non-cold-adapted (non-CA) virus grown at 37 C. The pathogenicity and immunogenicity were determined for CA and non-CA IBV in 1-day-old SPF chickens following intratracheal inoculation. The percentage of CA IBV-vaccinated chicks exhibiting respiratory disease exceeded 30% on only 1 day postinoculation (PI) (day 5 PI), compared with 8 days (days 2-9 PI) for birds given non-CA IBV. Mortality was 0% for CA IBV-vaccinated chickens and 6% for non-CA virus-vaccinated chickens. Microscopically, both CA and non-CA IBV caused diffuse tracheal deciliation, although mucosal hyperplasia, necrosis, and heterophil infiltration were more severe with non-CA IBV. Virus was reisolated from kidneys of chickens given CA IBV, suggesting the loss of the TS property. The instability of the TS property was confirmed by growth of the reisolated virus at 41 C. Both CA and non-CA viruses induced complete protection against homologous challenge virus infection of the upper respiratory tract.     

Viral pathogenesis of a nephrotropic infectious bronchitis virus isolated from commercial pullets.

Infectious bronchitis was diagnosed in 3-to-4-week-old pullets from an outbreak in a commercial flock in California. The disease was characterized by head swelling, watery discharge from the eyes and nostrils, and urates in kidneys. Mortality ranged from 1.8% to 12.5% per week. The isolation of a coronavirus from a suspension of pooled kidneys from clinically ill chickens at the fifth passage in 10-day-old chicken embryos, gross and histologic renal lesions, and seroconversion by enzyme-linked immunosorbent assay in inoculated birds suggested that the virus isolated was a nephrotrophic strain of infectious bronchitis virus (IBV). The virus isolate was found to be a previously unrecognized serotype, based on virus neutralization tests performed in embryonated chicken eggs. Nephropathogenicity of the IBV isolate was confirmed by inoculation of the viral isolate into specific-pathogen-free chicks and demonstration of renal lesions. The isolation of nephrotropic strains of IBV has not been reported previously from poultry in California.     

鸡4种病毒抗原液的浓缩及其四联油佐剂灭活苗的研制

本研究通过超滤浓缩技术对鸡新城疫病毒、传染性支气管炎病毒、产蛋下降综合征病毒和传染性法氏囊病病毒的尿囊液进行了10倍或10倍以上的浓缩处理，并按一定的比例配比研制成四联油乳剂灭活疫苗，对鸡的最小免疫剂量是0.25ml，免疫接种二周后，鸡新城疫和产蛋下降综合征病毒的HI抗体效价分别达到8log     

IBV感染雏鸡血清中SOD,GSH-Px活性与MDA含量的研究

将80只15日龄雏鸡随机分为对照组和试验组。试验组雏鸡用传染性支气管炎病毒尿囊液滴鼻染毒,攻毒后1,3,6,9,12d分别测定各组血清中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性与丙二醛(MDA)含量,研究血清中氧自由基在鸡传染性支气管炎发病过程中的动态变化。结果表明:试验组血清SOD,GSH-Px活性自攻毒后明显降低(P<0.05或P<0.01);MDA含量在攻毒后开始上升,且在感染后第6、第9天差异极显著(P<0.01)。提示氧化损伤可能参与调节了传染性支气管炎的发生发展过程。     

免疫器官中肾型鸡传染性支气管炎病毒的定位和动态分布

以鼠抗鸡肾型传染性支气管炎病毒（肾型IBV）的高免血清为一抗，辣根过氧化物酶（HRP）标记的羊抗鼠IgG为二抗，建立了检测石蜡切片肾型IBV抗原的间接酶标抗体染色技术。应用该技术对人工感染肾型IBV C9001株鸡免疫器官中的病毒进行了检测，结果胸腺和法氏囊是病毒主要侵害的免疫器官，脾脏，盲肠扁桃体仅呈一过性感染，哈氏腺未检测到，法氏囊从感染后2－12天，胸腺从感染后3－8天均检测到病毒抗原，阳性染色主要集中于法氏囊淋巴滤泡髓质区和胸腺小叶髓质区淋巴细胞和网状细胞胞浆内。     

几种病毒与禽病原性大肠杆菌的人工联合感染

以2种剂量的低致病性禽流感病毒(lowly pathogenic avian influenza virus,LPAIV)，传染性支气管炎病毒（infectious bronchitis virus,IBV)疫苗株H120和H52，新城疫病毒（Newcastle disese viurs,NDV)Lasota株分别于气管内注射10日龄易感鸡，2d后，气管注射禽病原性大肠杆菌O37株（O78），连续观察5d，结果，除LPAIV单独感染组有6．25％的死亡率外，其余各病毒单独接种组均健活；大肠杆菌O37株单独接种组的死亡率为62．50％，较高剂量的LPAIV，IBV H120和H52，NDV Lasota株与大肠杆菌O37株有效强的协同致病作用，死亡率分别达到81.25%,100.00%,93.75%和87.50%，而较低剂量的上述病毒则无明显的协同作用，IBV，NDV疫苗株与大肠杆菌联合接种组的多数死亡鸡病程推迟。     

Detection of infectious bronchitis virus antigen from experimentally infected chickens by indirect immunofluorescent assay with monoclonal antibody

Infectious bronchitis virus (IBV) was detected by indirect immunofluorescent assay with a monoclonal antibody (MAb-IFA). The monoclonal antibody was specific for the nucleocapsid protein of IBV strain M41. The MAb-IFA clearly detected IBV with high specificity in infected chicken kidney cells. The assay furthermore detected IBV in tracheal smears and sliced tracheas from experimentally infected chickens. The positive reaction was found to be longer than that in the virus recovery test. These results indicate that MAb-IFA is a useful method for the detection of IBV from chickens suspected to have infectious bronchitis.     

First evidence of the emergence of novel putative infectious bronchitis virus genotypes in Cuba

The emergence of new infectious bronchitis virus (IBV) genotypes or serotypes along with the poor cross-protection observed among IBV serotypes have complicated the avian infectious bronchitis (IB) control programs in different geographic regions. In Cuba, the lack of genetic information regarding IBV and the increasing epidemiological importance of this virus in Cuban chicken flocks demand further characterization of IBV isolates. In the present work, studies of genetic diversity and phylogenetic relationships among recent IBV isolates from Cuban chicken flocks showing respiratory disorders were performed. Two putative genotypes genetically different to the Massachusetts genotype H120 strain used in the Cuban vaccination program were found in the flocks assessed. In addition, a potential nephropathogenic IBV isolate was found by first time in Cuba.     

鸡传染性支气管炎病毒SC株N基因序列测定与同源性分析

从我国四川省一疑似鸡传染性支气管炎(Avianinfectious bronchitisvirus,IB)的雏鸡病料中成功分离到一株鸡传染性支气管炎病毒(Infectious Bronchitis Virus,IBV),命名为SC。病毒经鸡胚传代、血凝试验监测和负染电镜检查证实为IBV。自接毒鸡胚尿囊液中提取RNA后应用反转录-聚合酶链反应(RT-PCR)扩增得到了IBVSC株mRNA6 cDNA(编码N蛋白)。应用DNAstar5．06,Clustal1．8分析软件将克隆测序的N蛋白基因与Genbank中11株国内外参考毒株进行序列比较分析和同源性分析,发现IBV SC株变异独特,明显不同于国内外参考毒株。