Production of Escherichia coli-specific hybridomas by using gnotobiotic mice

Monoclonal antibodies provide a rapid and specific means of direct detection of microorganisms in water and food samples. However, monoclonal antibodies specific for some bacteria are difficult to obtain; a good example of such a bacterium is Escherichia coli. Gnotobiotic BALB/c mice immunized with whole-cell preparations of heat-treated strains of E. coli and subjected to high-frequency antigen injection showed a significant increase in the number of specific hybridomas produced. Fusions obtained by using regular BALB/c mice immunized by using standard immunization protocols produced nonspecific hybridomas. Twenty-one stable hybridomas that did not cross-react with Klebsiella pneumoniae ATCC 13883 or Citrobacter freundii 1604770 were obtained from gnotobiotic mice. The bacterial strains were selected for the specificity tests because of their high cross-reactivity, which has been detected in previous fusion experiments. The method of immunization described here offers the potential of improving the production of highly specific hybridomas for bacteria which have been difficult to obtain.     

Production and specificity of monoclonal antibodies and polyclonal antibodies to Escherichia coli

Monoclonal antibodies were produced to whole cells of heat-treated Escherichia coli. Balb/c mice were immunized with a pool of five strains of heat-treated E. coli , and the resulting hybridomas were screened by indirect immunoassay. E. coli strains other than those used for immunization were used for screening to detect hybridomas producing antibody that reacted with a large number of E. coli strains. Of 864 hybridomas, 32 reacted strongly with either two or all three of the strains used for screening; 15 were successfully cloned. Antibody from hybridoma 6H2 reacted with 35 of 68 (51%) E. coli ; of 13 non- E. coli tested, only Enterobacter agglomerans was weakly positive. Hybridoma 9B12 antibody reacted with all six E. coli tested. Hybridoma 9B12, however, stopped producing antibody. Five hybridomas produced antibody which reacted with a majority of the bacteria tested whereas antibodies from two other hybridomas reacted with several E. coli and non- E. coli. Polyclonal antibodies produced to two strains of E. coli varied in the numbers of E. coli with which they reacted; both antisera cross-reacted with several non- E. coli.     

Production and specificity of monoclonal antibodies and polyclonal antibodies to Escherichia coli

Monoclonal antibodies were produced to whole cells of heat-treated Escherichia coli. Balb/c mice were immunized with a pool of five strains of heat-treated E. coli, and the resulting hybridomas were screened by indirect immunoassay. E. coli strains other than those used for immunization were used for screening to detect hybridomas producing antibody that reacted with a large number of E. coli strains. Of 864 hybridomas, 32 reacted strongly with either two or all three of the strains used for screening; 15 were successfully cloned. Antibody from hybridoma 6H2 reacted with 35 of 68 (51%) E. coli; of 13 non-E. coli tested, only Enterobacter agglomerans was weakly positive. Hybridoma 9B12 antibody reacted with all six E. coli tested. Hybridoma 9B12, however, stopped producing antibody. Five hybridomas produced antibody which reacted with a majority of the bacteria tested whereas antibodies from two other hybridomas reacted with several E. coli and non-E. coli. Polyclonal antibodies produced to two strains of E. coli varied in the numbers of E. coli with which they reacted; both antisera cross-reacted with several non-E. coli.     

Analyses of Idiotypes on Anti-α-1, 6-Dextran Antibodies in Mice

When mice of strains C57BL/6, C3H/He, and BALB/c were immunized with native dextran B512, only a small amount of IgM antibody was produced, but a substantial amount of anti-dextran antibody of IgG class was produced after immunization with a conjugate of dextran T10 and keyhole limpet hemocyanin regardless of the mouse strain used. Isoelectric focusing (IEF) spectra revealed limited heterogeneity of anti-dextran antibody of IgG class with strict consistency in all individual sera from C57BL/6 mice, even after secondary immunization, whereas antibodies from C3H/He and BALB/c mice showed more heterogeneous IEF spectra with some individual variations. Rabbit anti-idiotypic (Id) antibodies were raised by immunization with a subfraction of anti-dextran antibody of IgG class from C57BL/6 mice, which showed major bands focused at around pH 7.7 upon IEF. It was found by using the anti-Id antibodies that virtually all anti-dextran antibody molecules of both IgG and IgM classes from C57BL/6 mice possessed common Id determinants which can be classified into two specificities, one specific for antibody from C57BL/6 mice and the other cross-reactive with antibodies from BALB/c and C3H/He mice. About 80% of the antibody molecules from BALB/c and less than 20% of those from C3H/He mice were positive for the interstrain cross-reactive Id. Both Id determinants seemed to be closely related to the antigen binding sites, or at least to reside in the vicinity of the antigen binding sites of anti-dextran antibody.     

Use of I region-restricted, antigen-specific T cell hybridomas to produce idiotypically specific anti-receptor antibodies

Murine T cell hybridomas bearing receptors for antigen plus I region gene products were used as immunogens in mice in an effort to raise anti-receptor antisera. The antisera were assayed for anti-receptor activity by the ability to inhibit interleukin 2 production by the T cell hybridomas stimulated by antigen and I region expressing antigen-presenting cells. The T cell hybridomas used in these experiments were made by fusing antigen-specific, I region-restricted BALB/c T cell blasts to the AKR thymoma, BW5147. Three groups of mice were immunized with the T cell hybridomas: (BALB/c X AKR)F1 animals, syngeneic to the hybridoma; (BALB.B X aKR)F1 animals, differing from the hybridomas at H2; and (C.B20 X AKR)F1 animals, differing from the hybridomas at Igh. Mice were immunized multiple times and sera from individual animals were assayed for anti-receptor antibodies. In all groups, some mice produced anti-receptor antibodies by the criterion that they were inhibitory in the assay mentioned above. The frequency of mice producing these inhibitory antibodies varied considerably between groups, with the (BALB.B X AKR)F1 animals producing these antibodies most frequently, and the (BALB/c X AKR)F1 animals producing them least often. All inhibitory antisera were idiotypically specific; they inhibited the response of the immunizing T cell hybridomas, but not the responses of closely related hybridomas with different specificities. Moreover, when they could be absorbed, the inhibitory antibodies could only be absorbed by the immunizing hybridoma. It is hoped that these antisera, and B cell hybridomas prepared from the immunized animals, will be useful in the elucidation of the structure of the receptors for antigen plus I region products on T cells.     

番茄环斑病毒单克隆抗体的制备

以纯化的番茄环斑病毒(Tomato ringspot virus,ToRSV)为抗原,注射免疫BALB/c小鼠,将免疫小鼠脾细胞与小鼠骨髓瘤细胞Sp2/0进行融合,经多次细胞筛选及克隆化,获得3株(A8、B7和G9)可分泌抗ToRSV单克隆抗体的杂交瘤细胞株,并以之分别制备小鼠腹水单克隆抗体。经酶联免疫吸附试验检测表明,该3株杂交瘤细胞腹水抗体效价在10-5～10-6之间,且均具有与ToRSV反应的特异性。     

Production and characterization of KDO-specific monoclonal antibodies recognizing lipopolysaccharides from heptoseless mutants of Salmonella

Abstract Hybrid cell lines producing monoclonal antibodies with specificity for the lipopolysaccharide (LPS) from the deep rough mutant Salmonella minnesota R595 have been established. Spleen cells from BALB/c mice immunized with live R595 bacteria were fused with Sp 2/0 myeloma cells and three hybridomas producing antibodies specific for heptoseless LPS from Salmonella were selected. All three monoclonal antibodies were shown to bind only to heptoseless, but 3-deoxy- d -manno-octulosonic acid (KDO) containing LPS when tested in enzyme-linked immunosorbent assay (ELISA) against a set of structurally defined LPS and lipid A from Salmonella, Shigella and Escherichia coli . Synthetic KDO was an efficient inhibitor of the antibody-R595 LPS interaction defining that KDO is in an immunodeterminant position interacting with the monoclonal antibodies.     

6种沙门菌单克隆抗体的制备和效能评价

目的：制备稳定、特异、高亲和性的分别针对甲型副伤寒沙门菌、乙型副伤寒沙门菌、丙型副伤寒沙门菌、肠炎沙门菌、伤寒沙门菌和猪霍乱沙门菌的单克隆抗体。方法：用甲醛灭活的菌液抗原免疫BALB／c小鼠,取脾细胞与SP2／0骨髓瘤细胞融合;用灭活的菌液包被酶标板,ELISA筛选阳性克隆株,建立细胞系;选取高效分泌杂交瘤细胞,常规制备腹水并纯化,进行单抗特异性与亲和性评价。结果：筛选得到分泌6种沙门菌相应单克隆抗体的杂交瘤细胞株,获得高亲和性单抗;所有单抗与大部分病原菌（包括7种沙门菌、3株志贺菌、2株李斯特菌、4株致病性大肠杆菌、2株霍乱弧菌）无交叉反应,但由于同类型O抗原的广泛分布,抗乙型副伤寒沙门菌单抗与鼠伤寒沙门菌、抗伤寒沙门菌单抗与肠炎沙门菌有明显的交叉反应。结论：沙门菌单抗的制备,为感染性腹泻的监测、诊断奠定了基础。     

消减免疫法制备克伦特罗单克隆抗体

目的：制备克伦特罗（CL）单克隆抗体。方法：重氮化法制备克伦特罗完全抗原,消减免疫法免疫BALB／c小鼠,常规杂交瘤技术制备抗克伦特罗单克隆抗体。结果：消减免疫法使小鼠获得了对BSA的耐受,单抗筛选过程中获得了高达8．2％的阳性率。最后得到了针对CL的特异性抗体。结论：用消减免疫法制备针对小分子污染物的单克隆抗体,可减少在制备单克隆抗体时筛选的工作量,可增加获得预期抗体的机会。     

Induction of anti-double stranded DNA antibodies in normal mice by immunization with bacterial DNA

Because of recent observations suggesting that bacterial DNA is immunogenic, the induction in normal mice of antibodies to Escherichia coli (EC) dsDNA was investigated. BALB/c and C57BL/6 mice were immunized with dsEC or ds calf thymus (CT) DNA complexed to methylated BSA in adjuvant; antibody responses were measured by ELISA. In both strains, dsEC DNA immunization induced a much higher anti-dsDNA response to dsEC DNA than did dsCT DNA immunization. Neither immunized group showed an appreciable antibody response when tested on dsCT DNA. Anti-dsDNA antibodies were also demonstrated by ELISA using synthetic DNA duplexes as well as a filter binding assay using 3H-labeled dsEC DNA as Ag. These results suggest that bacterial dsDNA is immunogenic and that at least some anti-dsDNA specificities can arise by immunization.     

抗人IgM单克隆抗体的研究—脾内免疫建立抗人IgM单克隆抗体杂交瘤细胞株

用多发性骨髓瘤病人血清中提纯的ＩｇＭ抗原,用脾内免疫ＢＡＬＢ／ｃ小鼠后与Ｓｐ２／Ｏ骨髓瘤细胞融合,获得了７株分泌人ＩｇＭ单克隆抗体的杂交瘤细胞株,分别命名为２５Ｇ１、２５Ｇ３、２５Ｇ４、２５Ｇ５、２５Ｄ２、２５Ｄ３和２５Ｄ５。注射同系小鼠后可诱生含较高效价抗人ＩｇＭ腹水（ＰＨＡ＝１２１２）。该杂交瘤细胞经组织培养传代半年,冻存１４个月后复苏,其分泌ＩｇＭ性能稳定。用ＰＨＡ、ＥＬＩＳＡ做人ＩｇＭ、ＩｇＧ、ＩｇＡ阻断试验,仅ＩｇＭ可阻断。用琼脂糖双扩散证明其与羊抗人ＩｇＭ有共同沉淀线     

抗嗜肺军团菌血清8型单克隆抗体的制备及双抗体夹心酶联免疫吸附试验检测法的建立

目的：制备针对嗜肺军团茵血清8型的单克隆抗体,并建立双抗体夹心酶联免疫吸附试验（ELISA）检测方法。方法：用甲醛灭活的嗜肺军团菌血清8型菌免疫BALB／c小鼠,采用杂交瘤技术制备抗嗜肺军团菌血清8型单克隆抗体,建立双抗夹心ELISA检测方法。结果：研制出8株能特异性分泌抗嗜肺军团菌血清8型单克隆抗体的杂交瘤细胞株,Ig类型分别为IgM（2株）、IgG,（1株）和IgG,（5株）;利用IgG1型单抗6G10与6C7配对,建立了双抗夹心ELISA检测方法,该方法的最低检出浓度为2．6×10^5cfu／mL,除与金黄色葡萄球菌有微弱的交叉反应外,与14株其他血清型嗜肺军团菌、17株非嗜肺军团菌及11株非军团菌均无交叉反应,具有较高的特异性。结论：制备了具有高特异性和亲和力的抗嗜肺军团菌血清8型单克隆抗体,并建立了双抗夹心EUSA检测方法。     

Application of an immune-tolerizing procedure to generate monoclonal antibodies specific to an alternate protein isoform of bovine growth hormone.

An immune-tolerizing protocol was employed to generate monoclonal antibodies to a variant protein isoform of bovine growth hormone arising from alternative pre-mRNA processing. Variant bovine growth hormone used for immunization was obtained by expression in bacteria and electroelution of the protein from preparative sodium dodecyl sulfate-polyacrylamide gels. Balb/c mice were first immunized with wild-type bovine growth hormone in the presence of the cytotoxic drug cyclophosphamide, thereby tolerizing the mouse to common epitopes shared among the two proteins. Subsequently, the mice were immunized with variant bovine growth hormone to produce antibodies specific to variant epitopes. Comparisons of fusions resulting from standard and tolerizing immunization protocols resulted in a significantly enhanced production of variant bovine growth hormone-specific antibodies as a result of the immunotolerizing protocol. The specificity of the antibodies to the variant growth hormone was substantiated by differential enzyme-linked immunosorbent assay and Western blot. Nearly all hybridomas positive for variant growth hormone were negative for wild-type growth hormone. Finally, the antibodies were used to demonstrate intracytoplasmic staining of COS I cells transiently transfected with a variant growth hormone-producing plasmid. Given the power of the polymerase chain reaction to conveniently clone alternatively processed mRNA species, followed by expression in bacteria to provide antigen, the immunotolerizing protocol provides a convenient general method for producing antibodies specific to desired protein isoforms.     

Monoclonal antibodies to Escherichia coli 50S ribosomes.

Hybridoma cell lines that produce monoclonal antibodies directed against 50S Ribosomal proteins have been isolated. Spleen cells (from BALB/c mice immunized with 50S ribosomal subunits extracted from Escherichia coli) were fused to mouse myeloma cell line SP2/O-Ag 14. The initial screening for antibody producing hybridomas was carried out by a double antibody sandwich method; hybridomas were subsequently cloned in soft agar. Antibodies were characterized by their specific binding to individual 50S ribsomal proteins separated on phosphocellulose columns and in two-dimensional polyacrylamide gels. The assignments were confirmed with purified single ribosomal proteins. Of four clones analyzed thus far, two are identical with specificity for r-protein L5. The other clones produce two different antibodies directed against r-protein L20. Each monoclonal antibody formed ribosome dimers visualizable in the electron microscope. Dimers could be reacted with a different second antibody to form chains containing 8 or more ribosomes, which may be useful for structural studies.     

Immunotherapy of murine sarcomas with auto-anti-idiotypic monoclonal antibodies which bind to tumor-specific T cells

Hybridomas producing monoclonal antibodies (mAb) were obtained from BALB/c mice immunized against either of two transplanted, chemically induced syngeneic sarcomas, MCA-1490 or MCA-1511. Two mAb, 4.72 and 5.96, were obtained, one from each immunization. They were found to have apparent anti-idiotypic specificity in that they, when injected s.c., primed naive BALB/c mice for delayed-type hypersensitivity that was specific for the immunizing tumor and required homology at genes linked to the Igh-1 allotype locus. Neither mAb bound tumor antigen. When mice with established transplants of MCA-1490 or MCA-1511 were treated by repeated i.p. injections of the appropriate anti-idiotypic mAb (4.72 and 5.96, respectively), a significant reduction in tumor growth was observed in those mice that had received the appropriate mAb. The idiotope defined by mAb 4.72 was expressed by T cells in mice responding to MCA-1490. mAb 4.72 bound to T cell suppressor factors that were specific for MCA-1490 and were derived from T cell hybridomas or sera of mice bearing MCA-1490. mAb 4.72 also bound to cells from lymph nodes draining the area of a growing MCA-1490 tumor. It was used, in combination with cell sorting, to establish a T cell line, which mediated delayed-type hypersensitivity to MCA-1490 and inhibited the outgrowth of MCA-1490 in BALB/c mice. Thus, mAb specific for idiotopes on T cells responding to syngeneic tumor antigen had both direct immunotherapeutic activity and could be used to establish cultures of tumor-reactive T cells.     

质粒DNA单次脾内注射制备单克隆抗体

探索一种新的快捷有效DNA免疫制备单克隆抗体的方法,辅助实现构建高通量无蛋白纯化体系单克隆抗体制备和筛选。分别通过“重叠PCR”和“无模板PCR”在pVAX1真核载体中分别引入IL-2信号肽、IgG kappa链信号肽构建分泌型真核表达载体,将代表抗原基因的profilin1基因克隆到经改造带有信号肽基因的表达载体上,构建重组质粒pVAX-IL2-prof1和pVAX-Igκ-prof1,单次脾内注射重组质粒DNA免疫BALB/c小鼠。经过细胞融合、ELISA筛选,获得两株抗profilin1的单克隆抗体。单抗亚型分别为IgM和IgG3。单次脾内质粒DNA免疫便捷有效,是制备单克隆抗体的有效方法。     

A study of autologous anti-idiotypic antibody-forming cells in mice of different ages and genetic backgrounds.

Antibody response to phosphorylcholine, an immunodominant epitope of Streptococcus pneumoniae R36a (Pn), is characterized by a public idiotype, T15, that is expressed on a large proportion of antibody molecules produced by all mouse inbred strains. The ability of the immune system to produce an autologous antibody to T15 upon immunization with Pn vaccine was investigated using a modified ELISA plaque assay for detection of single antibody-forming cells (AFC). The limit of ELISA assay for detection of specific anti-T15 AFC is approximately 300 cells/spleen. However, our studies failed to detect any autologous anti-T15 AFC in the course of the primary antibody response to Pn vaccine in young/adult (2-4 months) BALB/c and C57BL/6 mice. Aged mice (20-22 months) also failed to develop any specific auto-anti-T15 AFC upon the primary Pn immunization, despite the fact that the anti-Pn response in these animals changes both quantitatively and qualitatively. In order to generate specific anti-T15 AFC, BALB/c mice had to be immunized repeatedly with Pn vaccine (four weekly injections) or immunized directly with T15 protein in CFA. Different results were obtained with D1.LP mice that are low responders to Pn and express lower levels of T15 Id as compared to BALB/c. Young D1.LP mice produced high numbers of auto-anti-T15 AFC of both IgM and IgG isotypes following a single immunization with Pn vaccine. The kinetics of auto-anti-T15 response in D1.LP mice was similar to that of the antigen-specific response. These results demonstrate that the ability of the immune network to produce autologous antibody to a shared Id depends on the genetic makeup of the host, and that this response may be regulated by the level of Id expression.     

自噬相关基因LC3-I的基因表达及单克隆抗体的制备

目的：通过克隆LC3．I基因,体外原核表达LC3-I蛋白后制备抗LC3单克隆抗体,作为自噬研究中的标记分子检测自噬的发生和发展过程。方法：RT．PCR方法从RAW264．7细胞基因组中克隆LC3基因,亚克隆至pQE80L原核表达载体后转化E．cobDH5a进行诱导表达,SDS—PAGE电泳及Westemblot鉴定表达蛋白。蛋白纯化后免疫BALB／c小鼠。采用淋巴细胞杂交瘤技术,制备分泌抗LC3．I杂交瘤细胞株,体内诱生腹水制备mAb,间接ELISA法测定其效价,辛酸一硫酸铵沉淀法及亲和层析法纯化mAb。结果：成功克隆了LC3一I基因,并对其在E．coilDH5a进行诱导表达,SDS-PAGE分析表明在相对分子量Mr为20×10^3有特异条带,Westernblot验证表达产物具有一定的生物学活性。建立了3株稳定分泌特异性抗LC3-ImAb的杂交瘤细胞株,诱导产生的腹水获得的抗体效价在10^5-10^7之间,结论：在E．coli中对LC3-I进行表达,并制备特异性较强抗LC3-I蛋白的单克隆抗体。为自噬研究提供了良好的标记分子,可对自噬形成和发展进行有效的检测。     

PRODUCTION AND WESTERN BLOT CHARACTERIZATION OF MONOCLONAL ANTIBODIES SPECIFIC FOR CAMPYLOBACTER JEJUNI AND CAMPYLOBACTER COLI

Reference strains of the Lior serogroups of Campylobacter jejuni and C. coli most frequently encountered in human infections were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. Seven components appeared to be common to all strains. Purified components were obtained from one strain by electrophoretic separation and elution from preparative SDS-PAGE gels. The purified components were used to immunize BALB/c mice for monoclonal antibody production and to screen hybridoma tissue culture supernatants for specific antibody by enzyme immunoassay. Antibodies from selected hybridomas were characterized on western blots of C. jejuni, C. coli, C. fetus, Salmonella typhimurium, Proteus vulgaris, Citrobacter diversus and Escherichia coli whole cell lysates. At least nine of the monoclonal antibodies appeared to be specific for C. jejuni and C. coli and thus may be useful in tests for the rapid detection of these organisms in foods and other specimens.     

Immunochemical characteristics of synthetic peptides incorporating T- and B-cell epitopes nonspecific porins of pathogenic Yersinia

Multiple antigenic peptides (MAPs), a sequence which include common antigenic epitopes of outer membrane porins (OM) bacteria of the genus Yersinia (Y. pseudotuberculosis, Y. enterocolitica, Y. pestis), pathogenic for humans have been synthesized. After immunization of BALB/c mice the antiserum to the peptide have been obtained. With the help of ELISA we showed that these sera interact with porins isolated from OM pathogenic Yersinia, and MAP interact with antibodies in sera from rabbits immunized with individual porins, and with antibodies in sera of patients with intestinal yersiniosis and pseudotuberculosis.