Comparative studies on the antigenicity of extra- and intracellular viruses of fowl pox.

The intra- and extracellular virus of three strains of fowl pox virus, when precipitated in succession with different saturation of ammonium sulphate revealed three antigens in gel diffusion test in the precipitates obtained at 25%, 50% and 75% of saturation. Further analysis of each positive antigen by dot ELISA revealed that the extracellular virus of FS-8 and HP 1 strains possessed excess antigenic protein at 50% saturation compared to their intracellular viruses. While no difference between extra- and intracellular viruses of FS-4 strain was observed.     

Detection of camel pox and vaccinia viruses by polymerase chain reaction

PCR following two methods of DNA extraction was used to confirm the growth of camel pox virus (CPV) and vaccinia virus in cell culture and chorioallantoic membrane. Results were compared with the commonly used neutralization test. The first method of DNA extraction was accomplished by using viral DNA in tissue culture supernatant and Chorioallantoic membrane, which was released by initial heating for 15 min at 99°C followed by ordinary PCR. In the second method DNA was extracted by using DNA Isolation Kit from tissue culture supernatant and used as a template. Rapid identification and differentiation of CPV and Vaccinia virus were achieved by PCR and this assay proved to be fast and feasible, and can be an alternative to orthodox serological methods.     

The interferon sensitivity of selected porcine viruses.

The objective of this study was to compare the sensitivity of 11 porcine viruses to the antiviral effects of porcine interferon-alpha in serum from piglets which had been infected 19 h previously with transmissible gastroenteritis virus, and of porcine interferon-beta prepared in PK-15 cells by induction with polyinosinic:polycytidylic acid, in yield reduction assays in pig kidney cells which were treated with interferon before virus challenge, and both before and after virus challenge. The most sensitive virus to both types of interferon was vesicular stomatitis. A porcine isolate of bovine herpesvirus type 1, hemagglutinating encephalomyelitis virus and porcine enterovirus types 1 and 2 were also highly sensitive to interferon-alpha. There was little reduction in the yield of porcine parvovirus or porcine rotavirus, while swinepox, swine influenza and transmissible gastroenteritis viruses were intermediate in their sensitivity to interferon-alpha. In addition to vesicular stomatitis virus, porcine adenovirus type 3, swine influenza, hemagglutinating encephalomyelitis and porcine rotavirus were highly sensitive to interferon-beta, while swinepox, bovine herpesvirus type 1, porcine parvovirus, transmissible gastroenteritis and porcine enteroviruses were less sensitive than the above viruses to interferon-beta, although all showed significant reductions in virus yield.     

Induction of chicken interferon by avian infectious bronchitis virus.

The ability of nine strains of avian infectious bronchitis virus (IBV) to induce chicken interferon has been investigated using Semliki Forest virus for the tests. The Beaudette, H120 and Connecticut 46 strains induced interferon in the allantoic fluids of embryonated hens' eggs, the highest titre (1 : 30) being associated with Beaudette; but these as well as the Massachusetts M-41 and H52 strains failed to yield interferon in primary monolayer cultures of chick kidney cells as did all nine strains in organ cultures of chick embryo trachea. None of six strains of IBV investigated was susceptible to the inhibitory effects of chicken interferon.     

Isolation and identification of the Sersenk strain of goat pox virus in Iraq.

Goat pox virus was isolated during an outbreak of pox infection among goats in the Sersenk district, Iraq. The isolated virus grew on the chorioallantoic membranes of developing chick embryos and in primary lamb testis cell cultures. It was identified morphologically as a pox virus and serologically as a member of the Capripoxvirus group in the family Poxviridae. The isolated virus was designated the "Sersenk" strain.     

鸡痘鹌鹑化弱毒细胞苗接毒培养工艺探索

在鸡胚成纤维细胞(CEF)培养鸡痘鹌鹑化弱毒细胞苗的工艺中,采用同步接毒工艺,通过调整单位细胞浓度和单位病毒含量,以细胞单层形成时间和收获时间分别为24 h和96 h为标准,确定细胞浓度和接毒浓度分别为1.2×106 ～1.5×106个/mL和102 ～103 EID50/mL较为合适.     

Phylogenetic studies on lymphokines. Fish lymphocytes respond to human IL-1 and epithelial cells produce an IL-1 like factor

The results obtained indicate, that catfish peripheral blood lymphocytes recognize and respond to human IL-1. The second part of this report is dealing with a substance produced by carp epidermal cells with functional similarities to mammalian IL-1.     

山羊痘琼脂凝胶扩散(AGID)抗原的制备及初步应用

筛选所分离到的山羊痘云南省地方流行毒株KM株,应用牛睾丸原代及次代细胞进行病毒增殖、提纯及浓缩,制备山羊痘琼脂凝胶扩散试验(AGID)抗原。同时对该抗原进行抗原效价、判定标准、特异性、符合率及稳定性测定。测定结果显示该抗原效价为1∶4,且特异性及符合率高、稳定性好。并应用所制备抗原及参考阳性血清对采集自非疫点山羊血清186份,疫点390份,自然发病康复山羊血清46份,山羊痘免疫血清216份进行AGID初步应用。检测结果与流行病学相符合,证明我们所制备的山羊痘AGID抗原完全能够用于山羊痘抗体的检测及监测,且经济、简单、易操作,适于在基层单位推广应用。     

羊痘病毒多表位核酸疫苗的构建及表达

结合文献报道并通过计算机软件分析筛选出羊痘病毒(SGPV) A4同源核蛋白和A27、A33、B5、L1同源膜蛋白基因的T、B细胞优势抗原表位共6段,采用人工合成的方法将各抗原表位以柔性氨基酸(GPGPG)作为接头串联成一条全新的多表位嵌合基因E.将其克隆到真核表达载体pcDNA3.1(+)中,采用酶切分析与序列测定方法筛选鉴定阳性重组质粒,构建pcDNA3.1-E质粒.用脂质体法转染BHK-21细胞,通过间接免疫荧光(IFA)试验验证其表达效果;提取转染细胞总RNA,RT-PCR方法检测目的基因的转录.结果所构建的真核表达质粒在BHK-21细胞中能表达目的蛋白,RT-PCR方法检测到目的基因的转录;表明表达产物能与相应抗体特异性结合,具有一定的生物学活性和抗原性,有望成为抗SGPV的核酸疫苗.     

Serological and immunological studies of pleuropneumonia of swine caused by Haemophilus parahaemolyticus

The development of circulating antibodies for H. parahaemolyticus was studied in experimentally infected SPF pigs and in-contact SPF pigs. Blood serum titers were determined by a modified complement fixation test with normal SPF swine serum as a source of supplementary complement factor, and by an indirect haemagglutination test.CF and IHA titers became positive within the first 2 weeks following exposure to H. parahaemolyticus, and reached peak values after 2 to 7 weeks (Figs. 1 to 3). The exposed pigs proved immune, in that they showed no clinical symptoms on challenge after resp. 6, 9 and 11 weeks.While distinct titers were thus obtained with both tests in SPF swine experimentally exposed to H. parahaemolyticus, the CF test proved more specific than the IHA test when the 2 tests were compared in a field outbreak of polyserositis (Glässers disease) caused by H. parasuis. The CF test would therefore seem to be preferable to the IHA test in field diagnostic work (Table 1).A noticeable finding was that challenge did not elicit an anamnestic antibody response in any of the immune pigs (Figs. 1 to 3). This fact together with negative bacteriological findings in the animals in question would seem to suggest that the challenge dose was unable to establish a permanent infection in the respiratory tract of the immune pigs.     

Characterization of infectious laryngotracheitis viruses, antigenic comparison by kinetics of neutralization and immunization studies.

Five isolates of infectious laryngotracheitis virus were compared by pock formation on the chorioallantoic membrane of embryonated eggs, plaque size in chicken embryo kidney tissue culture, and antigenic relationship using reciprocal kinetics of neutralization. The A4557-5 strain of infectious laryngotracheitis virus, which causes mild respiratory disease, produced pocks with a zone of edema on the chorioallantoic membrane. A virulent virus (Virus 1), isolated from an outbreak of severe disease characterized by a diphtheritic laryngotracheitis, produced the largest plaques in chicken embryo kidney cell culture. Other virulent viruses (Viruses 2, 3 and V154) did not have unique growth characteristics when grown on the chorioallantoic membrane or in chicken embryo kidney cell culture. All viruses were closely related antigenically as shown by kinetics of neutralization but viruses 2 and 3 were not homogeneous with the other three viruses when neutralized by anti-V154 chicken serum. Following aerosol infection, chickens infected with the A4557-5 virus were immune to challenge with virulent V154 virus. However, in comparison to SA-2 virus, this virus was a less effective immunizing agent when administered by the vent or drinking water methods.