Evaluation of two monoclonal antibodies for serotyping Haemophilus paragallinarum

Two monoclonal antibodies (MAbs) were evaluated for their ability to serotype 108 isolates of Haemophilus paragallinarum. One MAb (E5C12D10) was raised against a Page serovar A strain and the other (F2E6) against a Page serovar C strain. In both dot blot and hemagglutination-inhibition tests, MAb E5C12D10 recognized the type strains of Page serovar A and Kume serovars A-1, A-2, A-3, and A-4. MAb F2E6 recognized the type strains of Page serovar C and Kume serovars C-1, C-2, and C-3. Neither antibody recognized the type strains of Page serovar B or Kume serovars B-1 and C-4. When evaluated with 97 field isolates in a dot blot test, the MAbs serotyped 81 isolates, which was better than agglutinin typing by the Page scheme (69 isolates serotyped). The field isolates that did not react with the MAbs were either Page serovar B/Kume serovar B-1 (three isolates), Page serovar C/Kume serovar C-4 (12 isolates), or nontypable by either the Page or Kume scheme (one isolate).     

Crossbreeding cattle in beef production programmes in Kenya

Data collected on a privately owned ranch located in the Machakos District of Kenya at approximately 2 degrees latitude south of the equator at an elevation varying from 1,675 to 2,000 m were analysed on five breed groups of cows: (1) purebred Boran, (2) 1/2 Charolais-1/2 Boran (1/2 C-1/2 B), (3) 3/4 Boran-1/4 Charolais (3/4 B-1/4 C), (4) 1/2 Ayrshire-1/2 Boran (1/2 A-1/2 B) and (5) 1/2 Santa Gertrudis-1/2 Boran (1/2 SG-1/2 B). The maternal traits evaluated included age at first calving, calving interval, calf weight at weaning and cow productivity index (calf weight weaned annually per cow calving). Mean cow productivity index for all cows was 192 kg; for purebred Boran, 174 kg; for 1/2 C-1/2 B, 200 kg; for 3/4 B-1/4 C, 191 kg; for 1/2 A-1/2 B, 210 kg; and for 1/2 SG-1/2 B, 185 kg. Cow breed groups 1/2 C-1/2 B, 3/4 B-1/4 C, 1/2 A-1/2 B and 1/2 SG-1/2 B exceeded (P less than 0.01) purebred Boran by 14.9, 9.8, 20.7 and 6.3%, respectively, in cow productivity index.     

马铃薯杂种优良株系遗传差异的AFLP分析

为明确从‘1867’ב陇薯7号’、‘MB09’ב陇薯7号’和‘MB09’ב陇薯6号’3个马铃薯杂交组合中选育出的17个杂种优良株系的遗传差异程度,用4个亲本材料作对照,利用AFLP分子标记技术对其进行了遗传差异分析。用筛选出的10对AFLP适宜引物进行PCR扩增共得到321个位点,多态性位点277个,多态性位点百分率87.29%。试验建立了各杂种优良株系的AFLP指纹图。21份马铃薯材料间的多态信息含量(PIC)平均为0.5617,Nei’s遗传多样性指数为0.3623,Shannon指数为0.5407。各材料间的平均遗传距离(GD)为0.5281,以GD值0.51为基准,21份材料分为4类:‘1867’、A-10、A-12、A-21和A-29为一类;‘陇薯6号’、‘陇薯7号’、A-14、A-23、A-26、B-13和B-14为一类;‘MB09’、B-1、B-2、B-7、B-15、B-20和C-22为一类;C-2和C-21为一类。该研究可为马铃薯杂交亲本的选择利用和杂种优良新品系的选育提供依据。     

Identification of a variable epitope on the Newcastle disease virus hemagglutinin–neuraminidase protein

Fifteen virulent Newcastle disease viruses (NDVs) were isolated from diseased birds in Eastern China in 2005. To investigate the antigenic variation in the epitopes on NDV hemagglutinin–neuraminidase (HN) protein, these isolates, together with six reference strains, were subjected to the hemagglutination inhibition (HI) tests using five HI-positive monoclonal antibodies (MAbs) against velogenic NDV strain ZJ1. The MAbs 2G5, 3A4, 3B5 and 6B1 recognized 12 of the 15 NDV isolates, and exhibited HI activity towards the six reference strains. However, these MAbs did not react with three local isolates, JS-02/05, JS-06/05 and JS-10/05. HN gene sequence analysis of all NDV strains revealed that these MAb-resistant NDV isolates possessed residue K at position 347 of the HN protein, whereas all remaining strains possessed E or G at the same site. To determine the contribution of the residue at position 347 to antigenic epitope formation, we generated by reverse genetics two recombinant viruses, ZJ1HNK with an E347K mutation on ZJ1 HN, and JSHNE with a K347E mutation on JS-06/05 HN. The HI test demonstrated that ZJ1HNK lost reactivity with MAbs 2G5, 3A4, 3B5 and 6B1, whereas JSHNE did react with these MAbs. Further verification by immunofluorescent assay demonstrated that residue 347 was a critical determinant for formation of the antigenic epitope (residues 345–353) on the HN protein.     

Development and characterization of monoclonal antibodies against FMD virus type Asia-1 and determination of antigenic variations in the field strains

Twelve mouse monoclonal antibodies (MAbs) were developed against an Indian vaccine strain of foot and mouth disease virus (FMDV) type Asia-1 WBN 117/85. The MAbs were tested for their ability to bind to whole virus particle, trypsin-treated 146S (TT-146S) virus particle, sub-viral (12S and disrupted virus) antigens by ELISA and to neutralize virus infectivity in cell culture. Extensive characterization of MAbs revealed the existence of three different groups based on the binding of non-overlapping epitopes. Eight type Asia-1 specific MAbs (RF7, RF8, RD10, RE11, RC11, RC10/O, RB11 and RC10/M), which formed group 1 (G1), were found to bind a neutralizing, trypsin-sensitive (TS) and conformational epitope. Two MAbs (WB8 and WC3) in group 2 (G2) were found to bind a non-neutralizing, trypsin-resistant, conformational and 12S-specific epitope, which was intertypically conserved in all the four serotypes of FMDV (O, A, C and Asia-1) prevalent in India. Two MAbs (KG10 and KF10), which formed group 3 (G3), were found to be against a non-neutralizing, TS and conformational epitope, common to types Asia-1 and A. Members of G1 were IgG2a isotype, while those of G2 and G3 were IgG1 and IgG2b isotypes, respectively. Antigenic analysis of 31 FMDV type Asia-1 field isolates and two vaccine strains, using a panel of type Asia-1-specific MAbs, revealed antigenic similarity of the virus isolates tested and non-existence of neutralization escape mutants. The developed MAbs have practical utility, especially in the manufacture of FMD vaccine, diagnosis and FMDV characterization.     

Expression of porcine interleukin-2 in Escherichia coli

A mature form of porcine interleukin-2 (IL-2) protein without signal peptides was expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli using pGEX vector. Since most of GST-IL-2 fusion protein was detected in an insoluble fraction on SDS-PAGE analysis, the insoluble fusion protein was solubilized by refolding procedure using urea. The recombinant IL-2 (rIL-2) was purified by a batch method using Glutathione Sepharose 4B and factor Xa digestion and used for preparation of antisera in mice. The antisera reacted with rIL-2 expressed in baculovirus system on immunoblot analysis. In addition, the purified rIL-2 showed a high biological activity on CTLL-2 proliferative response.     

抗蓝舌病病毒VP6和VP7蛋白单克隆抗体的制备及鉴定

为制备针对蓝舌病病毒(BTV)的单克隆抗体(MAb),本研究利用血清型1型BTV(BTV1)免疫BALB/c鼠,将其脾淋巴细胞与SP2/0进行融合,并用BTV1包被ELISA板,通过间接ELISA方法筛选出3株稳定分泌抗BTV1的MAb的杂交瘤细胞株(2B10、3D4和4H8)。利用表达BTV1主要蛋白的真核表达重组质粒转染BHK-21后,对所制备的杂交瘤细胞株上清进行间接免疫荧光(IFA)以及western blot鉴定,结果显示:2B10和4H8与VP7蛋白反应,而3D4与VP6蛋白反应。同时,IFA鉴定结果进一步表明,3株MAb与24个血清型的BTV均可以发生反应。本研究制备的MAb为建立BTV免疫学检测方法和相关病毒蛋白的功能研究奠定了基础。     

Production and characterization of monoclonal antibodies against an avian group A rotavirus.

Fifteen monoclonal antibodies (MAbs) against an avian group A rotavirus were cloned and characterized. Eight of the 15 MAbs had neutralizing activity (N-MAbs). Five of the N-MAbs (1G1, 5B8, 4E2, 3G1, 2E3) were VP4-specific by radioimmunoprecipitation assay (RIPA), and two N-MAbs (2D11, 6E8) were possibly VP7-specific (faint bands by RIPA). One N-MAb (4H12) of undefined protein specificity cross-reacted with serotype 3 simian rotaviruses. The other seven N-MAbs did not cross-react with any of the eight distinct serotypes of human and mammalian rotaviruses tested. Of the seven non-neutralizing MAbs, three were VP6-specific (3H10, 4B12, 5F6), two were VP8-specific (6C9, 1D1), one was VP4-specific (4E9), and one was of undefined protein specificity (1B11). Four non-neutralizing MAbs recognized only avian group A rotavirus in cell-culture immunofluorescence tests (6C9, 1D1, 4E9 and 5F6), whereas two MAbs (3H10 and 4B12) cross-reacted with all human and animal rotaviruses tested. The MAb 1B11 did not recognize any human rotavirus serotypes but cross-reacted with all nonhuman animal rotavirus serotypes. The MAbs produced in this study should be useful for the detection and further characterization of avian group A rotaviruses.     

Development and characterization of monoclonal antibodies to subgroup A avian leukosis virus

Avian leukosis virus subgroup A (ALV‐A) is a retrovirus which infects egg‐type chickens and is the main pathogen of lymphoid leukosis (LL) and myeloid leukosis (ML). In order to greatly enhance the diagnosis and treatment of clinical avian leukemia, two monoclonal antibodies (MAbs) to ALV‐A were developed by fusion between SP2/0 and spleen cells from mice immunized with expressed ALV‐A env‐gp85 protein. Using immunofluorescence assay (IFA), two MAbs reacted with ALV‐A, but not with subgroups B and J of ALV. Western blot tests showed that molecular weight of ALV‐A envelope glycoprotein recognized by MAbs was about 53 kD. Isotyping test revealed that two MAbs (A5C1 and A4C8) were IgG1 isotypes. These MAbs can be used for diagnosis and epidemiology of ALV‐A.     

Production and Characterization of Monoclonal Antibodies to Peste des Petits Ruminants (PPR) Virus

Peste des petits ruminants (PPR) is an acute, febrile viral disease of small ruminants, caused by a virus of the genus Morbillivirus. PPR and rinderpest viruses are antigenically related and need to be differentiated serologically. In the present study, 23 mouse monoclonal antibodies were produced by polyethyleneglycol (PEG)-mediated fusion of sensitized lymphocytes and myeloma cells. Among these, two belong to the IgM class and the remaining 21 to various subclasses of IgG. The MAbs from the IgG class designated 4B6 and 4B11 neutralized PPR virus in vitro. In radioimmunoprecipitation assay, 10 MAbs recognized nucleoprotein, 4 recognized the matrix protein and one each haemagglutinin and phosphoprotein. The remaining 7 MAbs failed to precipitate any defined viral protein. The reactivity pattern of the monoclonal antibodies in indirect ELISA indicated a close antigenic relationship within three Indian PPR (lineage 4) virus isolates and also within two rinderpest vaccine strains. All PPR virus isolates could be distinguished from rinderpest vaccine viruses on the basis of the reactivity pattern of all MAbs and anti-N protein MAbs. A set of six monoclonal antibodies specific to PPR virus could also be identified from the panel. From the panel of MAbs available, two MAbs were selected for diagnostic applications, one each for the detection of antigens and antibodies to PPR virus.     

Protection conferred by bivalent and trivalent infectious coryza bacterins against prevalent serovars of Avibacterium (Haemophilus) paragallinarum in Mexico

The protection and level of hemagglutination-inhibition (HI) antibodies conferred in infectious coryza bivalent- and trivalent-immunized chickens against Avibacterium (Haemophilus) paragallinarum field isolates of the prevalent serovars in Mexico (A-1, A-2, B-1, and C-2) were investigated. The bivalent bacterin (A-1 and C-1) conferred significant protection and increased HI antibodies against isolates of serovars A-1, A-2, and C-2, but not against a serovar B-1 isolate. The trivalent bacterin (A-1, B-1, and C-2) conferred protection and increased HI antibodies against all four of the isolates. The results confirmed that in poultry areas where serovar B-1 is prevalent, the inclusion of this serovar in bacterins is needed to confer protection against infectious coryza caused by A. (H.) paragallinarum isolates of serovar B-1.     

Pathogenicity of various adenovirus serotypes in the presence of Escherichia coli in chickens

Ten strains of adenovirus representing 10 serotypes were administered intratracheally to 3-week-old specific-pathogen-free chickens, which also received 2.9 X 10(5) colony-forming units of a pathogenic Escherichia coli intranasally. One group was given only E. coli, and one was retained as an uninoculated control. Gross pathologic alterations post-mortem were minimal and limited to multiple scattered, pale areas in the lungs of an occasional chicken in various groups. Histopathologic changes in the lungs were those of multifocal, interstitial, and occasionally diffuse pneumonia. Moderate to marked interstitial pneumonia was incited by adenovirus strains 75-1A, B-3 A-2, C-2B, and X-11; Ind-C, Stein, Tipton, J-2, and T-8 caused similar but milder lesions. Strains 75-1A, A-2, C-2B, T-8, and X-11 incited moderate to marked multifocal pneumonia; Ind-C, Stein, Tipton, J-2, and B-3 caused mild multifocal pneumonia. In all groups, the pneumonic lesions were more severe 5 days postinoculation than 12 days postinoculation. Bronchiolitis and tracheitis lesions also varied in severity with serotype. A mild hepatitis was seen with serotypes T-8 and 75-1A. Neither the uninoculated control group nor the group inoculated with only E. coli exhibited gross or histopathologic alterations.     

Serotyping of Haemophilus paragallinarum isolates from Mexico by the Kume hemagglutinin scheme

A total of 42 isolates of Haemophilus paragallinarum from Mexico were serotyped by the Kume hemagglutinin scheme. Serovars A-1, A-2, B-1, and C-2 were recognized among 11 (26.2%), 7 (16.6%), 4 (9.5%), and 14 (33.3%) isolates, respectively. A further six isolates (14.3%) showed hemagglutinating activity but could not be classified into any serovar. Commercial vaccines containing Kume serovars A-1, A-2, B-1, and C-2 may provide better protection than those bi- or trivalent infectious coryza vaccines currently used in Mexico.     

荣昌猪白细胞介素-6基因的克隆与序列分析

根据GenBank收录的猪白细胞介素-6(PIL-6)设计1对特异性引物,经刀豆蛋白素A(ConA)诱导猪淋巴细胞并提取总RNA,用RT-PCR方法扩增出荣昌猪IL-6的cDNA。将扩增基因连接到PMD18-T质粒上,经酶切鉴定和序列测定证明该序列是PIL-6。序列分析结果表明:该基因cDNA全长741 bp,开放阅读框由639个核苷酸组成,推测产生的编码产物由212个氨基酸组成。核酸序列分析比对发现:荣昌猪IL-6与GenBank已发表的IL-6序列的同源性较高,为99.8%~100%,氨基酸的同源性为99.5%~100%。对荣昌猪IL-6基因氨基酸的亲水性和蛋白表面可能性进行分析,表明其与IL-6基因氨基酸序列性质一致。     

表达A型口蹄疫病毒衣壳蛋白重组腺病毒的构建

为构建表达A型口蹄疫病毒(FMDV)衣壳蛋白的重组腺病毒,本研究通过人工合成A型FMDVP1-2A、2B和3C融合基因,将其克隆到腺病毒穿梭载体pShuttle-CMV中,利用E.coli BJ5183内同源重组将目的基因插入腺病毒骨架质粒pAdEasy-1中,获得携带A型FMDV P1-2A-2B-3C基因的重组AdEasy-1。该重组质粒经PacⅠ线性化后转染AD-293细胞,获得重组腺病毒rAd-A09。经PCR检测,该重组腺病毒在传代过程中目的基因稳定存在,病毒滴度在第8代时可达到108.5TCID50/mL。间接免疫荧光检测和western blot分析表明,rAd-A09在AD-293细胞中产生FMDV的结构蛋白VP0、VP1和VP3。该重组腺病毒的构建为口蹄疫新型疫苗的研究奠定了基础。     

鸡传染性贫血病毒VP3蛋白的原核表达及其单克隆抗体的研制

本研究首先利用同源重组一步克隆法将鸡传染性贫血病病毒(CIAV)的VP3基因克隆到pGEX-6P-1原核表达载体上,经IPTG诱导及SDS-PAGE分析成功获得了重组蛋白rGST-VP3的表达.随即以纯化的重组蛋白rGST-VP3免疫Balb/c小鼠,通过脾细胞与SP2/0细胞融合以及间接免疫荧光(IFA)筛选,获得2株稳定分泌CIAV-VP3抗体的杂交瘤细胞株,分别命名为CIAV-VP3-4D7和CIAV-VP3-4G8;亚型鉴定表明,CIAV-VP3-4D7和CIAV-VP3-4G8均为IgG1;效价测定发现,CIAV-VP3-4D7和CIAV-VP3-4G8的腹水间接免疫荧光效价分别为1:102400与1:12800;Western blot进一步证实,CIAV-VP3-4D7和CIAV-VP3-4G8均能识别重组蛋白rGST-VP3.本研究结果为后期研究VP3蛋白在CIAV致病中作用及其诱导凋亡分子机制奠定了坚实的物质基础.     

犬副流感病毒单克隆抗体的研制及其特性鉴定

为研制犬副流感特异性诊断试剂,我们以犬副流感病毒(CPIV)免疫8周龄BALB/c小鼠,采用淋巴细胞杂交瘤技术获得4株稳定分泌针对CPIV的单克隆抗体(MAb)细胞株,分别命名为4F386、584C9、4G7F4和4C9D8.4株MAb腹水针对CPIV的间接ELISA抗体效价达1:10~5～1:10~6,与犬瘟热病毒(CDV)和犬细小病毒(CPV)均不发生交叉反应.MAb 4F386和4C9D8为IgG,5B4C9和4G7F4为IgM.Western blot检测表明,4F386与CPIV的F蛋白发生特异性反应,4G7F4与CPW的HN蛋白发生特异性反应,而584C9和4C9D8不与变性的CPIV蛋白发生反应.4株MAb均具有中和病毒活性,间接免疫荧光检测均呈为阳性.本研究为进一步研制CPIV特异性诊断和治疗制剂创造了条件.     

Foot-and-mouth disease virus C3 Resende subtype analysed by means of competition RIA using neutralizing monoclonal antibodies.

Foot-and-mouth disease virus (FMDV) was analysed using 30 monoclonal antibodies (MAbs) obtained from Balb/c mice immunized with FMDV C3 Resende (C3R) subtype 7 and 14 days before fusion No. 15 and 16 respectively. Fourteen MAbs were neutralizing and by means of competition radioimmuno assay it was possible to classify them into four groups. The first group consisted of MAbs specific for three sequential and three conformational epitopes. The second group consisted of MAbs specific for two conformational and for one sequential epitope. The third and the fourth groups consisted only of one MAb each, being specific for conformationally and one sequentially dependent epitope, respectively.     

猪IL-10的原核表达及其单克隆抗体的制备

为了制备猪IL-10的单克隆抗体(MAb),本研究根据GenBank登录的猪白细胞介素10(PIL-10)基因序列设计两对特异性引物,利用套式PCR扩增PIL-10成熟蛋白编码基因(490bp),构建原核表达载体pET28a-PIL-10,并转化至大肠杆菌BL21,经IPTG诱导,SDS-PAGE和western blot分析鉴定,证明PIL-10重组蛋白获得表达。提取纯化该重组蛋白包涵体,免疫BALB/c小鼠,经过3次细胞融合,间接ELISA方法筛选,获得一株能稳定分泌抗猪IL-10MAb的杂交瘤细胞,将其命名为2F4。Western blot结果证明该MAb能够与重组蛋白发生特异性反应。间接ELISA测定细胞上清抗体效价为1∶1024,腹水效价为1∶128000,该MAb为IgG3亚型,轻链为λ型。杂交瘤细胞连续传代20代,分泌抗体的效价基本一致,从而为进一步建立猪IL-10的检测方法奠定了物质基础。     

Identification of B-cell epitopes in the NSP1 protein of porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) was divided into North American and European genotypes. NSP1 was an important non-structural protein of PRRSV, which was auto-cleaved from the replicase polyprotein into NSP1α and NSP1β subunits and played an important role in the immune suppression. In this study, six monoclonal antibodies (MAbs) against the recombinant PRRSV NSP1, expressed in Escherichia coli system, were screened out and identified. Western blot and IFA results indicated that 4 out of 6 MAbs recognized the recombinant NSP1α and 2 MAbs recognized NSP1β. Epitope mapping results indicated that MAb 4H2 recognized the linear epitopes E(54)EPLRW(59) in NSP1α, MAbs (2G5, 3E11 and 4D4) recognized the epitopes H(157)VLTNLP(163) in NSP1α, and MAbs 3C7 and 1H7 reacted with the epitopes 185aa to 232aa in NSP1β. Protein sequence alignment of NSP1 indicated E(54)EPLRW(59) was conserved in all North American PRRSV strains, whereas European type strains has variable amino acids in this region. The epitope H(157)VLTNLP(163) was relatively conserved among all PRRSV strains, except for a L162→S162 change in European type strains. The epitope 185-232aa was variable among North American PRRSV strains. These results may facilitate future investigations into the function of NSP1 of PRRSV and diagnostic methods for PRRSV infection.