Development and characterisation of an ultrasensitive monoclonal antibody for chloramphenicol

In this study, a highly sensitive monoclonal antibody (McAb) against chloramphenicol (CAP) was successfully raised and characterised by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Three antigens coupled with different proteins were synthesised and determined by the UV-vis method. After five rounds of immunisation, antisera were collected from six Balb/C mice and screened by ic-ELISA. The standard inhibition curve of one CAP McAb (labelled 6F11) showed the best sensitivity to CAP after optimisation of the principal working conditions. The half-maximal inhibition concentration (IC₅₀) was calculated to be 0.01 ng/mL and the linear working range was from 0.0028 ng/mL to 0.040 ng/mL with a correlation coefficient of 0.996. This McAb showed high specificity, with negligible cross-reactivities detected towards CAP analogues (florfinicol, florfinicol amine, thiamphenicol). The recovery rate was 98.9–106.8% while the coefficient of variation was 4.45–6.05%. The IC₅₀ value and other parameters obtained for this CAP McAb suggest that it is likely to have a promising future in further applications in combination with different analytical techniques.     

A hybridoma secreting a neutralising monoclonal antibody to egg drop syndrome 1976 virus

A hybridoma (HPRS/AM/1) secreting neutralising antibody to Egg drop syndrome 1976 virus strain D61 was established. This monoclonal antibody also neutralised two other strains tested thereby showing that all the strains possess at least one common antigenic determinant which is important in infection. However, this epitope was not involved in haemagglutination. The antigen was identified in the nuclei of infected chick kidney cells by an indirect fluorescent antibody test.     

Complement-independent neutralising monoclonal antibody with differential reactivity for strains of human cytomegalovirus

A mouse monoclonal antibody with complement-independent neutralising activity against cytomegalovirus (CMV) and reactive with the 86 kilodalton (kDa) viral glycoprotein H is described. Neutralisation tests against a range of different strains of CMV showed significant crossreactivity, but clear differences were evident between the two prototype viruses AD169 and Davis, and particularly between AD169 and several low-passage recent clinical isolates; CMV present in urine was neutralised weakly if at all.     

Immunochemical characterisation of a murine monoclonal anti-idiotypic antibody.

Y7, a murine monoclonal IgG1 kappa antibody against a human monoclonal IgM lambda DJ molecule, was affinity purified on an IgM lambda immunoaffinity column. As detected by enzyme-linked immunosorbent assay (ELISA) the isolated Y7 monoclonal antibody was shown to be not cross-reactive with human IgG, human secretory IgA, mu chain, lambda + kappa chains and another human monoclonal IgM lambda BR. Binding to the polyclonal human IgM standard in the same assay was about 30 percent. The epitope specificity of affinity purified and biotinylated Y7 MoAb was localized only in the nonreduced pepsin Fab fragments of IgM lambda DJ immunogen. As the immunogen was determined to be a specific antibody to phosphorylcholine, the specificity of Y7 MoAb was further ascertained in its capacity to induce 95% inhibition of immunogen binding for phosphorylcholine.     

抗克伦特罗单克隆抗体杂交瘤的建立及其分泌单抗的免疫学特性鉴定

目的 :建立抗克伦特罗 (CL)单克隆抗体杂交瘤细胞系 ,制备CL单克隆抗体 ,并鉴定其免疫学特性。方法 :用重氮化法将半抗原CL偶联于载体蛋白BSA ,形成结合抗原BSA CL ;以BSA CL免疫BALB/C小鼠 ,应用杂交瘤技术建立分泌CL单克隆抗体细胞株 ;用体内诱生腹水法生产CL单抗 ,硫酸钠盐析法提纯。应用抗小鼠同种型抗体测定单抗的同种型 ,用竞争性ELISA和胶体金膜层析试验测定CL单抗的反应特异性和反应动力学。结果 :筛选出C 4G1、C 2H6、C 2D6和C 4C94株高敏感性和高特异性杂交瘤生产单抗 ,其单抗的间接ELISA效价分别为 5× 10 -5、3× 10 -4、6× 10 -4、2× 10 -5;同种型分别为IgG1/κ、IgG1/κ、IgG2a/κ、IgG2a/λ。C 4G1的亲和力常数K =1 6 8× 10 8L/mol,C 2H6的亲和力常数K =1 3× 10 8L/mol。经WestGold蛋白质印迹鉴定单抗与CL特异性结合。C 4G1单抗对CL的半数抑制浓度 (IC50 )为 7 94ng/ml,对沙丁胺醇 (Sb)的IC50 为 10 0 0ng/ml,对肾上腺素、去甲肾上腺素、异丙肾上腺素和来克多巴胺的IC50 均≥ 6 4 0 0ng/ml;C 4G1单抗与Sb的交叉反应性为0 79% ,与异丙肾上腺素的交叉反应性为 0 12 % ,而与肾上腺素、去甲肾上腺素、来克多巴胺、各类抗生素及多种维生素均无交叉反应性。结论 :用单克隆抗体杂交瘤技术     

Protective titres of measles neutralising antibody

A nation-wide measles outbreak occurred in 1988 in Taiwan. A retrospective cohort study was conducted to define the protective titre of measles neutralising (NT) antibody. Paired sera collected in 1987 and 1988 were available from 190 individuals born in 1984 who had participated in an annual hepatitis B immunisation follow-up from 1986 to 1991. Measles NT titres were quantified using a standardised neutralisation enzyme immunoassay. Measles infection was defined as a >/=4-fold rise in NT titre or seroconversion between paired sera. Symptomatic measles infection was ascribed to individuals who had measles infection and who reported measles-like symptoms between 1987 and 1988. Results demonstrated a dose-response relationship between pre-exposure NT titres and protection against measles infection. 47 of 48 individuals with measles infection in 1988 had pre-exposure NT titres 1, 000 mIU/ml may prevent measles infection and NT titres >500 mIU/ml may prevent symptomatic infection but vaccinees with undetectable or low NT titres may not necessarily be susceptible to symptomatic infection.     

Development of syngeneic monoclonal anti-idiotype antibodies to mouse monoclonal anti-asialoglycoprotein receptor antibody

Anti-idiotype antibodies (Ab2) play an important role in the homeostasis of immune responses and are related to the development and the disease activity of certain autoimmune diseases. The asialoglycoprotein receptor (ASGPR) is considered one of the target antigens in the pathogenesis of autoimmune chronic active hepatitis (AIH). We previously developed a mouse monoclonal antibody (clone 8D7) which recognizes rat and human ASGPR. In this study, to help investigate the anti-ASGPR antibody-anti-idiotype antibody network in patients with AIH, we developed a syngeneic mouse monoclonal Ab2 to the 8D7 anti-ASGPR antibody (Ab1). One clone, designated as 3C8, tested positive for specific reactivity to 8D7-Ab1 and did not bind to other irrelevant immunoglobulins. By competitive inhibition assays, the binding of 8D7-Ab1 to liver membrane extracts, i.e., the crude antigen preparation, was inhibited by 3C8-Ab2 in a dose-dependent manner, and the binding of 8D7-Ab1 to 3C8-Ab2 was inhibited by the liver membrane extracts. In the immunohistochemical analysis, 3C8-Ab2 blocked the specific staining of sinusoidal margins of rat hepatocytes by 8D7-Ab1. These results suggest that 3C8 anti-idiotype antibody recognizes the specific idiotypic determinants within the antigen-binding site of 8D7-Ab1.     

促肾上腺皮质激素单克隆抗体的筛选和鉴定

目的制备促肾上腺皮质激素 ( ACTH)单克隆抗体 ,拟建立高灵敏度 ACTH- IRMA或 EL ISA。方法 ACTH1 - 1 3、ACTH1 - 2 8、ACTH 1 - 39和 ACTH1 8- 39分别与牛血清白蛋白偶联制备免疫原 ,在背部皮下和腹腔注射免疫 BAL B/ c鼠。按常规方法进行细胞融合 ,以 RIA法检测培养上清液 ,阳性孔经亚克隆 ,获得 2株分泌特异性抗体的杂交瘤细胞株 ;瘤细胞种于预致敏的BAL B/ c鼠腹腔 ,批量生产单抗性腹水 ;琼脂扩散法鉴定抗体类型 ;利用标准曲线的参数计算单抗的亲合常数 ;亲合纯化单抗并进行抗体固化试验。结果从 ACTH1 - 2 8免疫鼠获得单抗株为 5 G2 ,从 ACTH1 - 1 3免疫鼠获得单抗株为 D3 ;单抗腹水 5 0 %结合率时腹水最终稀释度分别为 5× 10 3和 2× 10 3;抗体类型均为 Ig G1/λ;5 G2和 D3亲合常数分别为 5 .1× 10 9L M- 1 和 4 .9× 10 7L M- 1 ;抗体包被实验显示 5 G2和 D3的固化抗体量分别为 1.4μg和 8.8μg时结合率达到饱和。结论 5 G2和 D3可以用于构建灵敏的 ACTH- IRMA或 EL ISA。     

Production and characterisation of a monoclonal antibody to human papillomavirus type 16 using recombinant vaccinia virus.

A monoclonal antibody was raised against the major capsid protein L1 of human papillomavirus type 16, using a recombinant vaccinia virus that expresses the L1 protein, as a target for screening. This antibody, designated CAMVIR-1, reacted with a 56 kilodalton protein in cells infected with L1-vaccinia virus, and the protein was present in a predominantly nuclear location. The antibody also detects the HPV-16 L1 antigen in formalin fixed, paraffin wax embedded biopsy specimens and on routine cervical smears. The antibody reacts strongly and consistently with biopsy specimens containing HPV-16 or HPV-33, but very weak reactions were occasionally observed with biopsy specimens or smears containing HPV-6 or HPV-11. The potential advantages of using a vaccinia recombinant are (i) the target protein is synthesised in a eukoryotic cell so that its "processing" and location are normal; (ii) cells infected with vaccinia recombinants can be subjected to various fixing procedures similar to those used for routine clinical material. This greatly increases the probability that an identified antibody will be useful in a clinical setting.     

Molecular characterization of a panel of murine monoclonal antibodies specific for the SARS-coronavirus

The availability of monoclonal antibodies (mAbs) specific for the SARS-coronavirus (SARS-CoV) is important for the development of both diagnostic tools and treatment of infection. A molecular characterization of nine monoclonal antibodies raised in immune mice, using highly purified, inactivated SARS-CoV as the inoculating antigen, is presented in this report. These antibodies are specific for numerous viral protein targets, and six of them are able to effectively neutralize SARS-CoV in vitro, including one with a neutralizing titre of 0.075 nM. A phylogenetic analysis of the heavy and light chain sequences reveals that the mAbs share considerable homology. The majority of the heavy chains belong to a single Ig germline V-gene family, while considerably more sequence variation is evident in the light chain sequences. These analyses demonstrate that neutralization ability can be correlated with specific murine V(H)-gene alleles. For instance, one evident trend is high sequence conservation in the V(H) chains of the neutralizing mAbs, particularly in CDR-1 and CDR-2. The results suggest that optimization of murine mAbs for neutralization of SARS-CoV infection will likely be possible, and will aid in the development of diagnostic tools and passive treatments for SARS-CoV infection.     

Development of technology for linking photosensitizers to a model monoclonal antibody

A procedure is described whereby the photosensitizer, benzoporphyrin derivative monoacid ring A (BPD-MA) was covalently linked to a model monoclonal antibody in a manner which is reproducible, quantifiable, and retains both the biological activity of the antibody and the cytotoxicity of the photosensitizer. Preliminary steps involved the linkage of BPD-MA to a modified polyvinyl alcohol (PVA) backbone, followed by conjugation to the antibody using heterobifunctional linking technology. Briefly, polyvinyl alcohol (MW ca. 10,000) was modified with 2-fluoro-1-methyl pyridinium toluene-4-sulfonate and 1,6-hexanediamine to produce side chains containing free amino groups. The free carboxyl group of BPD-MA was utilized to conjugate photosensitizer molecules to modified PVA using a standard carbodiimide reaction. Final linkage of the PVA-BPD to a model monoclonal antibody involved further substitution of the carrier with 3-mercaptopropionic acid and carbodiimide to introduce 3-4 sulfhydryl residues per carrier molecule, and introduction of sulfo-m-maleimidobenzoyl-N-hydroxysulfosuccinimide ester residues to the monoclonal (3-4 residues/molecule). Conjugation was effected by reaction of the two species at pH 5.5 for 18 h. Detailed methodology and tests for efficacy of the procedure are provided.     

Production and characterisation of a human monoclonal antibody to cytomegalovirus and its use in an early nuclear fluorescence assay

A human monoclonal antibody to cytomegalovirus (CMV) was produced by transforming peripheral blood mononuclear cells of a patient with recent CMV infection. It is directed against a late antigen located in the nucleus of CMV infected fibroblasts at 24-72 hours postinfection and immuneprecipitates 65K and 48K proteins from 35S-labelled CMV infected cells. Results of its use in an early nuclear fluorescence assay for rapid diagnosis are presented.     

Detection of transmissible gastroenteritis virus neutralising antibody in cats

Summary High titres of neutralising activity to transmissible gastroenteritis virus (TGEV), a porcine coronavirus, were found in sera and peritoneal fluids from cats infected with feline infectious peritonitis (FIP). A small proportion of cats, from a hospital population unaffected by FIP, also had neutralising activity. Procedures to remove non-specific viral inhibitors, including treatment by heat inactivation, trypsin, sulphydryl reagent and kaolin absorption were unsuccessful. The active component was unable to neutralise another porcine coronavirus, haemagglutinating encephalomyelitis virus or the porcine enterovirus, Talfan. Gel filtration of feline sera and peritoneal fluid demonstrated high levels of the neutralising activity in the area corresponding to 7S IgG, which could be removed by absorption with specific anti-IgG serum and these properties are suggested to be consistent with those of antibody. These findings imply that there is a coronavirus in cats which is antigenically related to TGEV and its possible nature is discussed.With 4 Figures     

A mouse monoclonal antibody to the TSHR

INTRODUCTION: Mouse monoclonal antibodies (mAbs) with the ability to inhibit thyrotropin (TSH) binding to the TSH receptor (TSHR) are useful tools to study TSH-TSHR interaction. The 3C3 mAb we produced was found to inhibit binding of TSH to human (h)TSHR but not to porcine (p)TSHR. MATERIAL/METHODS: Purified 3C3 immunoglobulin G (IgG) and its antibody-binding fragment were prepared using standard methods and their ability to inhibit TSH binding to hTSHR or pTSHR was analyzed using a coated tube assay. The TSHR epitope reactive with 3C3 IgG was determined using Western blotting, ELISA based on peptides corresponding to the TSHR sequence, and the SPOT synthesis technique. RNA was isolated from 3C3 hybridoma cells and the mAb variable (V) region genes were sequenced and analyzed. RESULTS: 3C3 mAb had a 1 x 108 l/mol binding affinity to the hTSHR as assessed by Scatchard analysis. 3C3 reacted with the hTSHR region between amino acids (aa) 212-230, and two aa differences were found between the corresponding regions in the hTSHR and pTSHR. The light chain (LC) genes of 3C3 were derived from the Vk21 germ-line (97.6% homology) and Jk2 genes. The heavy chain (HC) genes were from the V130 germ-line (94.6% homology) combined with a D gene (not identified) and JH3 gene. The replacement/ silent mutation ratios of 6.0 and 6.5 for the LC and the HC V regions, respectively, indicated that 3C3 underwent antigen-driven maturation. CONCLUSIONS: Mouse mAbs of this type should be useful in studying the interactions between the TSHR, TSH, and mAbs in more detail.     

Colonic pericrypt sheath cells: characterisation of cell type with new monoclonal antibody.

A new monoclonal antibody, PR 2D3, was raised against a crude homogenate of normal colorectal mucosa and found to react with the cells in the pericrypt sheath. It also reacted with smooth muscle throughout the body and, in specific sites, with those mesenchymal cells known as myofibroblasts. It did not react with cardiac or skeletal muscle, nor with fibroblasts. PR 2D3 is an IgG1 antibody and identifies a membrane component of about 140 K molecular weight. The pericrypt cells have been described as fibroblasts, but in view of the specificity of PR 2D3 for smooth muscle, and its selective staining of the colonic pericrypt cells, this cell type was re-examined for other smooth muscle properties. Ultrastructurally, the cells had many characteristics in common with smooth muscle and were identical with the myofibroblasts of the umbilical cord. On immunocytochemical examination they were found to contain desmin, myosin, and filamin. The confirmation that the pericrypt cells are myofibroblasts suggest that they have both contractile and secretory roles.     

一株A和B亚群禽白血病病毒特异性单克隆抗体的制备及其特性

目的:制备A和B亚群禽白血病病毒(Avian leukosis virus,ALV)特异性单克隆抗体。方法:用ALV-A-SDAU09C1株的env-gp85基因的PCR产物构建重组表达性质粒pET32a-SDAU09C1-gp85,经IPTG诱导后,表达分子量为53 kD的ALV-A囊膜gp85蛋白与GST的融合蛋白,将表达产物免疫BALB/c小鼠,取其脾脏细胞与骨髓瘤细胞SP2/0进行融合,筛选杂交瘤细胞株。结果:获得了1株(A6D1株)能与A和B亚群ALV发生反应但不与J亚群ALV反应的杂交瘤细胞株。Western blot试验结果表明,单克隆抗体识别的A和B亚群ALV囊膜糖蛋白的分子量为53 kD。在IFA中,这株单克隆抗体可以与所试验的3株ALV-A和1株ALV-B毒株反应,而与4株ALV-J亚群的毒株不反应。结论:A6D1株单克隆抗体可以用于A和B亚群ALV感染的诊断和流行病学调查,弥补了目前只有J亚群ALV特异性单克隆抗体可用的不足。     

A sensitive assay for detection and measurement of neutralising antibody to human immunodeficiency virus.

An assay based on the inhibition of syncytium formation in C8166 cells was developed to measure low levels of neutralising antibody (NT-AB) to human immunodeficiency virus (HIV) and to detect cross-reactivity between virus strains. The relationship between virus challenge and antibody titre was represented by a tripartite curve which was essentially linear over moderate levels of virus input. Based on these findings, antibody titres were standardised against 100 TCID50 of challenge virus. However, lower virus inocula were found to detect minimum levels of antibody. Reproducibility of antibody titres between tests was high, with variation generally lying within one dilution step. The improved sensitivity of the technique allowed detection of NT-ABs in animals immunised with immune-stimulating complexes (ISCOMS) incorporating HIV antigens. Consistent levels of cross-reactivity between HIV strains was demonstrated, indicating the presence of distinct viral groups, from which dominant isolates may be chosen for use in vaccination studies.     

Production and characterisation of a monoclonal antibody to a cell-surface, glucomannoprotein constituent of Candida albicans and other pathogenic Candida species

A murine monoclonal antibody (MAB AF-1) class IgM was raised to a soluble glucomannoprotein extract (GMP) of Candida albicans. Agglutination and indirect immunofluorescence assays with purified MAB showed that AF-1 was directed against a cell-surface epitope shared by C. albicans serotypes A and B, C. tropicalis, C. guilliermondii and C. viswanathii, but not by C. krusei, C. parapsilosis, C. kefyr (pseudotropicalis) and T. glabrata. Treatment with heat, protease or periodate-treated GMP and with other cell-wall extracts of C. albicans provided evidence that the epitope recognised by MAB AF-1 is carried by the polysaccharide moiety of cell-surface glucomannoprotein molecule(s).     

Production and characterization of monoclonal antibody to gentamicin

Splenocytes from BALB/c mice immunized with a gentamicin-hemocyanin conjugate were fused with X63-Ag8.653 murine myeloma cells to produce hybridomas that secreted monoclonal antibody to gentamicin. Sixteen positive clones were obtained. The monoclonal antibody chosen for a gentamicin immunoassay has been characterized with respect to class, subclass, type of light chain, electrophoretic homogeneity, and binding affinity. Gentamicin monoclonal antibody purified from mouse ascites fluid was analyzed by immunoelectrophoresis, double immunodiffusion, enzyme-linked immunosorbent assay (ELISA), and polyacrylamide gel electrophoresis (PAGE). The results show that the antibody is an IgG2a (kappa). Two bands were detected when the purified antibody was electrophoresed on polyacrylamide gels: a major band and a less mobile minor component (5.6% of the major band). Both were IgG2a (kappa). The major band contained antibody which bound 2.1 moles of the substrate-labeled gentamicin derivative, beta-galactosyl-umbelliferone sisomicin, per mole of IgG, whereas one mole of the minor band bound only 0.095 moles of the substrate-labeled conjugate. The antibody has an affinity constant of 1.22 X 10(10) M-1.