Antibody directed against Marek's disease-associated tumor surface antigen can be eluted from Marek's disease tumor cells.

Antibody directed against Marek's disease-associated tumor surface antigen (MATSA) was eluted from tumor cells of lymphomas and peripheral blood lymphocytes that were isolated from Marek's disease virus-infected chickens. Feather follicular Marek's disease virus (MDV) antigen could not be demonstrated with this antibody by indirect immunofluorescent (IF) staining. Monoclonal antibody directed against MATSA could completely block the activity of eluted antibody and vice versa. By indirect IF staining using eluted antibody and fluorescein isothiocyanate (FITC) labelled antichicken globulin conjugate. MATSA-bearing cells were detected in MDV infected and herpes virus of turkey (HVT) vaccinated birds. Blocking of immunoglobulin molecules present on B-cells by anti-chicken globulin is critical in this test.     

Immunization trials with virus-free antigens against Marek''s disease

Additional immunization trials were performed to study the immunogenicity of the purified skin antigen of Marek's disease virus which was inoculated, together with Freud's complete adjuvant, into one-day-old chicks. As compared to non-vaccinated chickens and also to chickens vaccinated by herpesvirus turkey (which reduced the mortality by 45.54%) the purified skin antigen reduced the mortality by 69.50%.

In the case of immunization with protein extract from the lymphoblastoid cell line of Marek's disease lymphomes mixed with natural dsRNA showed 38.99% reduction of mortality. DEAE-dextran which had exerted an adjuvant effect in our previous report did not by itself reduce mortality caused by Marek's disease.

Groups of chickens vaccinated with the turkey herpesvirus with protein extract mixed with dsRNA, and a group of chickens inoculated with 0.04 g.ml⁻¹ DEAE-dextran, had a higher whole complement activity in pooled serum from 107 days after challenge than chickens free of Marek's disease.     

鸡马立克氏病活疫苗鸡马立克氏病双价活疫苗鸡马立克氏病火鸡疱疹病毒活疫苗

鸡马立克氏病活疫苗　　鸡马立克氏病活疫苗(Marek’sDiseaseVac cine,Living)系用自然低毒力的马立克氏病病毒弱毒株,接种鸡胚成纤维细胞培养,收获感染细胞,加入适宜冷冻保护液制成。用于预防鸡马立克氏病(MD)。【性状】　淡红色细胞悬液。【用途】　用于预防鸡马立克氏病。各种品种1日龄雏鸡均可使用。注苗后8日可产生免疫力。【用法与用量】　肌肉或皮下注射。按瓶签注明的羽份,用稀释液稀释,每羽0.2mL。(含2000PFU)。【免疫期】　1年6个月。【注意事项】　①疫苗必须在液氮中贮藏及运输。②从液氮中取出后应迅速放于37℃温水中,待完…     

胎儿弯杆菌表面蛋白SapA抗原单克隆抗体的制备

用原核表达的重组胎儿弯杆菌毒力因子表面蛋白(rSapA-N)免疫小鼠,采用细胞融合技术,共获得2株抗rSapA-N的单克隆抗体(MAb),经Ⅰg亚类鉴定,均为ⅠgG1,轻链为K链;Western blot证实这2株MAb均能与rSapA-N发生特异性反应,而与其它蛋白则不发生反应;以这2株MAb的杂交瘤细胞制备腹水,效价达到1:100 000和1:60 000.本研究制备的MAb,为研究和检测胎儿弯杆菌提供了一种重要的手段.     

Studies on the mechanism of vaccinal immunity to Marek''s disease

Current knowledge of the nature of the antigens and of the host immune responses in vaccinal immunity to Marek's disease is reviewed. It is suggested that a two-step mechanism of resistance operates. The first step involves humoral and cell-mediated responses directed against viral antigens; the second step occurs after challenge with Marek's disease virus and consists of cellmediated responses directed against tumour cells.     

Effect of diffferent levels of maternally derived antibodies on protection against infectious bursal disease virus

Fertile eggs were obtained from three different broiler breeder flocks with different levels of virus neutralizing antibodies to infectious bursal disease virus. Egg yolk from these flocks was tested for antibody titers by the virus neutralization test. Flock I eggs had no antibodies, flock II had medium level antibodies (1:200-1600; geometric mean = 1:975), and flock III had a high level of antibodies (1:1600-6400; geometric mean = 1:3365). Chicks from the above flocks were challenged each with 10(2) 50% embryo infective dose of the IN serotype 1 variant virus at 1, 2, and 4 wk of age and examined at 5 and 11 days postchallenge. The average organ/body weight ratios were calculated and statistically analyzed. Chicks with no maternal antibodies were not protected at any age. Chicks with medium levels of maternal antibodies were protected when challenged at 1 and 2 wk of age. Chicks with high levels of maternally derived antibodies were protected when challenged at all the ages tested. The above results were statistically significant (P < 0.05).     

Preparation of monoclonal antibodies against cell surface antigens in cattle

The BALB/c mice were immunized three times with bovine lymphocytes and thrombocytes in vivo. Besides, dissociated spleens of the mice were immunized with bovine lymphocytes in vitro. Hybridomas producing monoclonal antibodies were formed as a result of the fusion of the spleen cells with the murine myeloma cells. On the whole, four fusions were performed after immunization in vivo and three fusions after immunization in vitro, and 70 stable hybridoma clones were obtained. Five monoclonal antibodies exhibited an identical specific reaction only with bovine thrombocytes, two antibodies reacted only with a certain limited population of bovine spleen cells. The remaining monoclonal antibodies exhibited no tissue specificity and were bound to the lymphocytes of peripheral blood, lymph nodes, thymus, and spleen, to thrombocytes, liver cells, and spermatozoa, but never to erythrocytes. As for the amount of the obtained hybridomas and specific antibodies, no significant difference was observed in the effectiveness of in vivo and in vitro immunization.     

Monoclonal antibodies directed against Brucella abortus cell surface antigens

A panel of monoclonal antibodies (MAb) has been raised against Brucella abortus cell surface antigens from mice immunized with either heat/phenol treated or UV killed bacterial suspensions of B. abortus. The hybridomas were screened by either a microagglutination procedure or by an indirect enzyme immunoassay (EIA) on sonicated bacterial preparations. From a large number of MAb generated by various procedures, two distinct types of MAb emerged. The most numerous type was capable of agglutinating B. abortus and reacting with a soluble preparation of lipopolysaccharide (LPS). A second type was not capable of agglutinating the bacterial suspensions or of binding to the soluble LPS preparation but reacted with an antigen present in bacterial sonicates. Two MAb of this type react differentially with sonicates prepared from virulent and avirulent strains of B. abortus. There appeared to be sufficient evidence from our analysis of the relative degree of cross reaction with antigens present on a range of B. abortus strains and Brucella and xenogenic bacterial species to conclude that each of the seven MAb was recognising a separate antigenic site on the B. abortus cell surface.     

Monoclonal internal image anti-idiotype antibodies of Theileria sergenti merozoite surface antigen

Monoclonal anti-idiotype antibodies against monoclonal antibody (23C11) to intraerythrocytic merozoites of Theileria sergenti were prepared and examined by indirect immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA). Three anti-idiotype antibodies containing antibodies against interspecies cross-reactive idiotopes and/or an internal image of Theileria sergenti merozoite were found. The presence of antibody against Theileria sergenti was shown by ELISA in these anti-idiotype antibodies induced anti-anti-idiotype antibodies.     

Correlation between maternal serum antibodies and protection against bovine rotavirus diarrhea in calves

The correlation between maternal serum antibodies in beef calves at 2 days old and protection against diarrhea induced by natural bovine rotavirus (BRV) infection was examined. Virus neutralizing (VN) antibody titers against BRV in sera from calves that developed diarrhea by BRV infection within 14 days of age (BRV-diarrheal calves) were significantly lower than those from calves that had no diarrhea. In the BRV-diarrheal calves, a positive correlation was found between the VN antibody titers and age of the onset of diarrhea. There were negative correlations between the VN antibody titers and duration of the diarrhea, VN antibody titers and cumulative diarrhea scores, and the VN antibody titers and duration of virus shedding. These results suggest that the VN antibody titers against BRV in newborn calf serum could be an indicator of protection against BRV-induced diarrhea.     

Protective immunity against Newcastle disease: the role of antibodies specific to Newcastle disease virus polypeptides

Studies were performed to determine if passive immunization with hyperimmune sera generated to specific Newcastle disease virus (NDV) proteins conferred protection against virus challenge. Six groups of 3-wk-old chickens were passively immunized with antiserum against either hemagglutinin-neuraminidase/fusion, (HN/F) protein, nucleoprotein/phosphoprotein (NP/P), Matrix (M) protein, a mixture of all NDV proteins (ALL), intact ultraviolet-inactivated NDV (UVNDV), or negative sera. Blood samples were collected 2 days postimmunization, and the birds were challenged with Texas GB strain of NDV. Antibody titers were detected from those recipient birds that had received the antisera against the HN/F, ALL, or UVNDV by a hemagglutination inhibition test, an enzyme-linked immunosorbent assay (ELISA), and a virus neutralization test. Antibodies were detected only by the ELISA from the birds that had received antisera against NP/P and M protein. Antibody titers in the recipient birds dropped by two dilutions (log2) after 2 days postinjection. Birds passively immunized with antisera against HN/F, ALL, and UVNDV were protected from challenge, whereas chickens passively immunized with antisera against NP/P and M protein and specific-pathogen-free sera developed clinical signs of Newcastle disease. The challenge virus was recovered from the tracheas of all passively immunized groups. The presence of neutralizing antibodies to NDV provided protection from clinical disease but was unable to prevent virus shedding from the trachea.     

MD病毒抗独特型抗体的研制

制备鸡马立克氏病病毒(MDV)抗独特型抗体(Ab2),探讨Ab2模拟抗原诱导免疫应答的能力.用MDV免疫SPF鸡,分离提纯鸡抗MD-IgG(Ab1),Ab1免疫BALB/C鼠,用鼠脾细胞与SP2/0细胞制备Ab2杂交瘤细胞株,间接ELISA筛选阳性杂交瘤细胞株,经克隆、纯化2×株抗MDV独特型抗体杂交瘤细胞株(6E5,7A12),其中6E5培养上清、腹水ELISA效价分别为4000×、10000×,免疫20 d攻毒,具有抗MDV感染保护.     

Isolation of very virulent Marek''s disease viruses from vaccinated chickens in Australia

Very virulent Marek's disease viruses (vvMDV), defined as isolates against which the herpesvirus of turkey (HVT) vaccine provide poor protection, have been isolated from poultry flocks in both the United States and Europe. Twenty-one samples from vaccinated Australian flocks, experiencing problems with excessive Marek's disease (MD), were tested for the presence of transmissible MD viruses (MDV). Of the 16 samples which contained a transmissible agent, 14 were pathogenic in chickens, based on the development of MD lesions or depression of the bursa/body weight ratio. Of the pathogenic isolates which have been successfully typed 10 were serotype 1, and one was serotype 2 MDV. Pathogenicity of isolates varied. Several isolates caused tumours in 20-30% of both vaccinated and unvaccinated chickens. Two isolates, MPF6 and MPF23, caused tumours in more than 50% of chickens. When MPF6 and MPF23 were tested in vaccine trials bivalent vaccine gave no better protection against development of MD lesions than a monovalent vaccine. Isolate MPF23 was so pathogenic that lesions were produced in all chickens, regardless of the vaccine protocol used. Therefore vvMDV have been isolated in Australia, and unlike the vaccines tested overseas, bivalent Australian vaccines do not appear to provide greater protection against these vvMDV.     

Production and characterization of monoclonal antibodies against chicken lymphocyte surface antigens

A panel of monoclonal antibodies (mAbs) with specificity for chicken lymphocyte surface antigens was established and characterized based on their reactivities against chicken lymphoid cells and tumor cell lines on flow cytometry. Three mAbs (7-3G-2, 7-2E-8, and JB-2) reacted preferentially with thymocytes, however, none of them reacted with Marek's disease derived T lymphoblastoid cell lines. Four mAbs (6-27A-1, 4-5C-5, Lc-4, and Lc-6) reacted with spleen cells and peripheral blood leukocytes as well as thymocytes. All seven mAbs reacted with chicken embryonic thymocytes from day 12 of embryonic life onward. All mAbs showed no reactivity against bursal lymphocytes.     

抗禽白血病p27抗原单克隆抗体的制备与鉴定

检测p27抗原的检测试剂在禽白血病的研究和防治方面有着极其重要的作用.为研究国产的禽白血病诊断试剂,利用禽白血病各亚群病毒的p27蛋白很保守的特点,我们将原核表达的禽白血病p27蛋白作为抗原,免疫8周龄的BALB/C小鼠,利用淋巴细胞杂交瘤技术,获得三株能稳定分泌特异性单克隆抗体的杂交瘤细胞株.通过Western-blotting和ELISA的结果分析证明,三株单抗与原核表达得p27蛋白和禽白血病各亚群病毒反应,而不与禽流感病毒等反应.可以看出,这三株单抗在ALV的抗原分析、血清学诊断和疫苗质量监测以及禽白血病污染细胞检测等方面有着极其重要的应用价值.