Comparison of the kinetics of the specific cellular immune response to duck hepatitis B virus in infected and immune ducks.

The kinetics of the cell mediated immune response by ducks acutely and chronically infected with, or immune to infection by duck hepatitis B virus (DHBV) was determined. This was measured by an antigen specific blastogenesis assay to duck hepatitis B surface antigen (DHBsAg) and duck hepatitis B core antigen (DHBcAg) using peripheral blood mononuclear cells (PBMC). The three outcomes of acute infection by DHBV were either clearance from both serum and liver, clearance from serum but not liver, or the development of persistent viraemia. Acutely infected ducks that failed to clear the infection also failed to develop a significant cellular immune response to both antigens. Ducks with chronic infection acquired as neonates or as the result of the failure to clear acute infection had an increasing cellular immune response over time. Two groups of immune ducks were examined. These were either ducks that had become immune following infection or that had been vaccinated. Both groups of ducks demonstrated significant cellular responses following challenge with DHBV irrespective of the level of their responses before challenge. However, there was a reduction in the response of their PBMC over a 4-week-period postchallenge. The range of cellular immune responses to DHBV antigens observed in this study has a number of counterparts in hepatitis B infection of humans. Coupled with the defined clinical outcomes that can be established in the duck/DHBV model, further study of the cellular immune response to DHBV is warranted.     

Humoral immune response of calves to bluetongue virus infection

Humoral immune responses of 7 calves to bluetongue virus (BTV) infection were evaluated by plaque-reduction assay and immunoblotting. Most readily interpretable results were obtained with the immunoblot assay when colostrum-deprived calves were used, and sera were reacted with proteins in partially purified extracts of BTV. Viremia persisted in calves for 35 to 56 days, and BTV coexisted in blood for several weeks with virus-specific neutralizing antibody. Calves developed antibody to virus protein 2, the major determinant of virus neutralization, at 14 to 28 days after inoculation; this time interval also coincided with the appearance of neutralizing antibody in serum. Virus clearance in BTV-infected calves did not coincide with humoral immune responses to protein 2 or other virion proteins.     

Comparison of precipitin antibodies and virus-neutralizing antibodies to infectious bursal disease virus

Three hundred twenty-two serum samples from commercial pullets and multiplier breeders were analyzed for agar-gel precipitin (AGP) antibodies and virus-neutralizing (VN) antibodies to infectious bursal disease virus. Two hundred thirty-four of these sera were AGP-positive, and 88 were AGP-negative. The geometric mean of the reciprocal of the VN titers for the AGP-positive sera was 208.7, and 232 (99.1%) had a VN titer of 1:16 or greater. In contrast, the geometric mean of the reciprocal of the VN titers for the AGP-negative sera was 6.1, but 53 (60.2%) had a VN titer ranging from 1:4 to 1:256. When the AGP test was compared with the VN test, the sensitivity and specificity, respectively, of the AGP test were 81.5% and 100%.     

Thermostability of duck hepatitis virus.

The comparative thermostability of 4 duck hepatitis (DH) viruses were tested at various temperatures for different times. Titer of duckling-passaged, pathogenic DH virus decreased from 10(4.50) to 10(2.33) and 10(2.20) median infective doses (ID50/0.1 ml, respectively, in 2 tests; titer of chicken embryo-passaged, nonpathogenic, but embryo-lethal, DH virus decreased from 10(6.00) to 10(0.46) and from 10(6.62) to 10(0.63) ID50/0.1 ml, respectively; duck embryo fibroblast culture-passaged and duck embryo liver cell culture-passaged, chicken ebryo-infective, but nonlethal, DH viruses were completely inactivated or nearly so after being kept at 56 C for 30 minutes. Duckling-passaged DH virus was not detected on day 21, whereas 10(0.62) ID50 of chicken embryo-passaged DH virus per 0.1 ml remained on day 32 when being kept at 37 C. Titer of chicken embryo-passaged DH virus decreased from 10(7.00) to 10(1.16) ID50/0.1 ml after being kept at room at room temperature for 150 days, to 10(5.17) ID50/0.1 ml after being kept at 4 C for 70 weeks, to 10(6.17) ID50/0.1 ml after being kept at -20 C for 70 weeks, and to 10(6.38) ID50/0.1 ml after being kept at -60 C for 1 year.     

鸭肝炎病毒单克隆抗体的研制

以反复冻融、氯仿处理、滤膜过滤、PEG反透析浓缩和分子筛层析的方法纯化DHV免疫BALB／c小鼠，同时作为包被抗原建立了筛选抗DHV阳性杂交瘤细胞株的间接ELISA方法，经特异性和重复性试验，效果良好。经一系列融合、筛选，成功获得阳性杂交瘤细胞株4株，并制备出了腹水，分别命名为285、2E8、5E6和6C11。特性鉴定结果表明4株单抗ELISA效价均比较高且特异性好，中和特性稍差，和两株Ⅰ型标准毒以及在山东分离到的几株病毒均有交叉反应。     

鸡抗鸭病毒性肝炎(DVH)高免卵黄抗体的研制

应用雏鸭肝炎病毒鸡胚化弱毒株和ＤＶＨ油乳剂苗免疫鸡制备了高免卵黄抗体。通过实验室试验及临床应用,表明卵黄抗体治ＤＶＨ的疗效取决于卵黄抗体的呼效价和治疗的时间。卵黄抗体的中和效价应达２＾８．５以上,并且在感染ＤＶＨ２４ｈ以内对雏鸭进行肌肉注射,免疫效果为最适宜。     

Humoral immune response to human cytomegalovirus proteins: a brief review.

Although human cytomegalovirus (HCMV) has a genome of 150 x 10(6) Da, and a protein-coding content of over 200 open reading frames, few viral proteins seem able to elicit a strong antibody response in the natural host during viral infection. The immunodominant polypeptides include a component of 72 kDa among immediate early proteins, a polypeptide of 52 kDa among delayed early proteins and a glycoprotein complex of 58 and 93-130 kDa and two phosphoproteins of mol. wt 150 and 65 kDa among the structural proteins. Following a general overview of the humoral immune response, this brief survey mainly deals with the antibody response to these proteins. As significant epitopes of the major HCMV immunogenic polypeptides have been expressed in procaryotic cells over the last few years, an overview of the state of the art in this particular field will also be given.     

Assessment of the immune response to duck plague vaccinations

An experiment was conducted to assess the immune responses of ducks to duck plague (DP) vaccinations employing one commercial and one laboratory-adapted (LA) DP vaccines. Virus neutralisation and leucocyte migration-inhibition tests were conducted at regular intervals before and after vaccinations. Similarly, ducks in vaccinated and control groups were subjected to challenge infection with virulent DP virus.The commercial vaccine yielded a poor immune response and partial protection on challenge whereas satisfactory responses were obtained in ducks receiving two doses of LA vaccine. The humoral as well as cellular factors were stimulated indicating possible involvement of both the immune responses in the protection from duck plague.     

Humoral immune response to feline immunodeficiency virus in cats with experimentally induced and naturally acquired infections.

Sera from cats with naturally acquired and experimentally induced feline immunodeficiency virus (FIV) infections were tested by immunoblot analysis, radioimmunoprecipitation assay (RIPA), and a complex trapping/blocking ELISA. In sequentially obtained samples from experimentally inoculated cats, antibodies against the envelope protein gp120 and the core protein p15 were the first to appear, as indicated by results of RIPA, using lysates of FIV-infected lymphocytes. Antibodies could be detected as early as 2 weeks after infection, followed by a response against p24, p43, and p50. By immunoblot analysis, p24 and p15 were the first proteins detectable between postinoculation weeks 3 and 5; an anti-envelope response was never found by use of this assay, but was found by RIPA. Using the latter test, most sera of naturally infected cats were found to recognize the major core protein p24 in addition to 1 or more minor core proteins. All 40 sera tested precipitated the envelope protein; 3 reacted exclusively with it. A complex trapping/blocking ELISA was developed to quantitate the anti-p24 response. Sera from healthy FIV-infected cats were shown to have higher anti-p24 titer than did those from diseased cats.     

Humoral immune responses of cats to feline infectious peritonitis virus infection.

Immunoperoxidase antibody (IPA) method as a titrating method of feline infectious peritonitis (FIP) virus (FIPV) was developed for titrating antibody to FIPV (IPA-titer). By this method the immune responses of the cats that had been infected with FIPV, were traced. The infected cats could be grouped into three types by their immune response to FIPV and clinical appearances. Type I cats lived for a long time, formed a major group among infected cats, had 160 to 1 x 10(4) IPA-titers, and showed healthy appearances without any changes both on autopsy and histopathologically. From among type I cats, type II cats appeared sporadically with rapid elevation of IPA titers to 3.2 x 10(5) and showing clinical signs of FIP, and died. Type III cats lived healthily for a long time with gradual elevation of IPA-titers to a plateau of about 1 x 10(5), then showed neuronal disorder of hind leg paralysis with the descending IPA-titers to 2 x 10(4), and died. Thus, typical FIP appeared as a hyper-immune disease. Other related problems are discussed.     

鸭病毒性肝炎精制蛋黄抗体保存期的测定

将3批（0501、0502、0503）鸭病毒性肝炎精制蛋黄抗体,置于不同温度条件下保存,间隔一定的时间抽取样品,测定样品的中和抗体效价和攻毒保护率。结果表明：3批病毒性肝炎精制蛋黄抗体在-20℃保存24个月,在2～8℃保存18个月,25℃保存6个月,均达到标准规定的要求。     

Active immunisation of ducklings against duck virus hepatitis.

Egg-attenuated duck hepatitis type (Rispens H55) was exhaustively tested as a potential vaccine under controlled conditions in ducklings fully susceptible to the disease at day 2 after hatching. Data are presented which indicate that this vaccine fulfils essential criteria of efficacy in terms of (a) the optimal age at which successful vaccination is practicable (day 2 or earlier), (b) the rapidity of onset of immunity (in 48 to 72 hours), (c) the high level of immunity induced (88.0 to 94.0 per cent), (d) the persistence of this degree of immunity in the individual bird throughout the period when it would otherwise be at risk (until the end of the fourth week of life) and (e) the consistency of the effects of the vaccine in successive groups of ducklings hatched over a four year period. Employed as a vaccine. H55 was completely innocuous to the vaccinated ducklings under laboratory conditions.     

Intestinal mucosal immune response against virulent duck enteritis virus infection in ducklings

Duck virus enteritis (DVE) is an acute and contagious herpes virus infection of duck, geese and swans with high morbidity and mortality. The development of specific mucosal immune system against duck enteritis virus (DEV) infection for ducks has been hindered by a lack of knowledge concerning the purification of immunoglobulin A (IgA) of duck. In the present work, the method for purification of duck immunoglobulin A was developed, and the induction of intestinal mucosal immune responses against DEV was studied by orally infected ducklings with virulent DEV. The results showed that a continuous increased DEV DNA levels were observed in blood and various organs examined of orally infected ducklings throughout the infection, which was accompanied by the development of infection in ducklings from mild progressed to severe pathological lesions. Furthermore, a marked increased level of DEV-specific IgA and IgG antibodies in bile, serum and the intestinal tract, as well as the density of IgA⁺ cells in intestine were detected between 1 and 12 days p.i., followed by a drastic reduction of the antibody levels and the density of IgA⁺ cells at 15 days p.i. The results indicate that the DVE infection can stimulate both IgA-dominated antibody immune responses in the intestinal tract, and IgG-dominated antibody systemic immunity in the serum of ducklings orally inoculated with virulent DEV. The severe lesions of the villus epithelial cells and the lymphoid organs can suppress the intestinal mucosal immune responses.     

雏鸭病毒性肝炎的研究进展

雏鸭病毒性肝炎（DuckViralHepatitis，DVH）是由鸭肝炎病毒（DuckHepatitisVirus，DHV）引起雏鸭的一种高度致死性、传播迅速的病毒性疾病，以肝炎为其主要特征。鸭肝炎病毒有三个血清型，可分别引起Ⅰ型、II型和III型雏鸭病毒性肝炎，如果防制不当，死亡率很高，对养鸭场会造成很大的经济损失。１．１Ⅰ型DVHⅠ型DVH最早由Levine和Hofstad于１９４５年在美国发现。Levine和Fabricant（１９５０年）用鸡胚分离到了Ⅰ型DHV。１９５３年后，加拿大、英国、德国、意大利、匈牙利、前苏联、印度、日本等国相继报道了该病。我国黄均…