Monoclonal antibodies to bovine blood group antigens

Hybridomas were made by fusing mouse myeloma cells with spleen cells from mice immunized with bovine red cells. Sixteen cloned lines which secreted haemolytic monoclonal antibodies reacting with antigens in the A, B, F, Z and S blood group systems were established; one of the antibodies identified a new factor in the B system. Extensive tests on red cells from 1000 animals indicated that several of the antibodies are suitable for use in routine blood typing; others are of potential use for genetic studies of the bovine blood group systems.     

Bovine monoclonal alloantibodies to blood group antigens prepared by murine x bovine or (murine x bovine) x bovine interspecies fusions.

In order to obtain monoclonal alloantibodies against bovine blood group antigens, lymph node cells from calves immunized with bovine red blood cells (RBC) were fused with either murine NSO/1 myeloma cells or a HAT sensitive murine x bovine heterohybridoma cell line. Both fusion partners resulted in heterohybridoma cell lines, producing monoclonal alloantibodies against bovine red blood cell antigens. Several clones produced antibodies against identical antigens and some of these clones have been further analysed. The antibodies produced by these selected cell lines have been compared with conventional polyclonal antisera used in bovine blood typing service. Thus extensive tests--including the ISAG Comparison Tests 1989/90 and 1991/92--have proved that monoclonal alloantibodies specific for the internationally recognized bovine red cell antigens A2, I1, O1, Q, A', B', Q', C1, R1, X1, S and Z have been produced. The Q, A', B', and C1 antibodies react weakly with certain phenogroups, whereas the A2, I1, O1, Q', R1, X1, S and Z antibodies have proved to be excellent blood typing reagents and have now substituted the polyclonal antisera in routine bovine blood typing in our laboratory.     

Analysis of Clonorchis sinensis antigens and diagnosis of clonorchiasis using monoclonal antibodies.

Clonorchis sinensis is a common parasite of man in Korea. Researches on the specific antigens of C. sinensis would be valuable not only because those elucidate the molecular characteristics of this fluke but also because it is applicable to immunodiagnosis. Although many monoclonal antibodies have been used in the field of parasite immunology, few articles on monoclonal antibodies against C. sinensis have been published so far. The aim of this study was to analyze C. sinensis antigens recognized by monoclonal antibodies, and to set up ELISA-inhibition test using C. sinensis specific monoclonal antibodies for improved specificity of immunodiagnostic tests. By fusion between spleen cells of the mice immunized with C. sinensis water-soluble crude adult worm antigens and plasmacytoma cells of mouse origin, 29 hybridoma clones secreting anti-C. sinensis monoclonal antibodies were made, and 8 clones among those were found specific. After cell cloning, isotypes of 6 selected specific monoclonal antibodies were determined to be IgG1, IgG2b and IgA. Four exposed antigenic determinants of natural infection were recognized by different specific monoclonal antibodies. By enzyme-immunoelectrotransfer blot, 10 KD, 34 KD antigenic determinants were found to be reacted with CsHyb 0714-20, CsHyb 0605-10 monoclonal antibodies, respectively. The antigenic determinant recognized by CsHyb 0714-20 monoclonal antibody was revealed to be located at the surface and parenchyme of a parasite by indirect immunofluorescent antibody technique, and those reacted with CsHyb 0605-10, CsHyb 0714-25 monoclonal antibodies were found at the parenchyme and intestine. The antigenic determinant reacted with CsHyb 0605-23 monoclonal antibody was found mainly around the uterine eggs. Four antigenic determinants recognized by specific monoclonal antibodies were all found to be present in the early eluted fractions of C. sinensis antigens separated by Sephadex G-200 gel filtration. By conventional ELISA, 75% of clonorchiasis cases were found positive, but 7.1% of normal controls and 37.5% of paragonimiasis cases showed false positives. However, by ELISA-inhibition test using C. sinensis specific monoclonal antibody (CsHyb 0605-23), 77.1% of clonorchiasis cases were found positive, and there were no false positives in normal controls or paragonimiasis cases, indicating 100% specificity.(ABSTRACT TRUNCATED AT 400 WORDS)     

Isolation and characterization of monoclonal antibodies reactive with endothelial cells

Monoclonal antibodies were generated to antigens on cultured human umbilical vein endothelial cells. Spleen cells from BALB/c mice, immunized with low passage cultures of human umbilical vein endothelial cells, were fused with the non-secretory myeloma line, P3 x 63Ag 8.653. Hybridoma supernatants were screened for the desired immunological reactivity using ELISA binding assays. Hybridomas secreting antibodies reacting with the immunizing endothelial cells, but not with peripheral blood mononuclear cells, were cloned by limiting dilution and three stable clones were chosen for study. Further testing by ELISA revealed that each antibody displayed a unique pattern of reactivity. One antibody, 14E5, reacted with the macrophage-like cell line DHL-2, cultured macrophages derived from peripheral blood monocytes, and macrophages derived from malignant effusions. The antibody failed to react with fibroblasts or bovine endothelial cells. The second antibody, 12C6, reacted with human and primate fibroblasts and endothelial cells derived from bovine arteries, but not with mature macrophages. The third clone, 10B9, reacted only with the immunizing endothelial cells and the immature-macrophage line U-937. All three antibodies failed to react with long-term human B or T lymphoblastoid cell lines, leukemic cell lines, or murine macrophage lines. None of the antibodies reacted with a battery of human epithelial derived cell lines or primary cultures of human epithelial cells. Indirect immunofluorescence assays revealed that the antigens were expressed on the cell surface. These antibodies should prove useful as differentiation markers of human endothelial cells and in studies of endothelial cell function.     

Characteristics of human NK clones: target specificity and phenotype

Clones derived from purified human large granular lymphocytes (LGL) of three different donors were expanded in culture medium supplemented with interleukin 2 (IL 2). Their cytotoxic activity was tested in a 51Cr-release cytotoxicity assay against a panel of three to five NK-susceptible tumor cell lines. Of 196 LGL clones tested, only 44 (22.4%) displayed significant cytotoxic activity. A heterogeneous pattern of reactivity was seen; 26 clones (59%) killed all the targets within the panel tested, whereas 18 clones (41%) had a more restricted specificity. Among these 18 clones, 12 lysed only one target (K562, six clones; ADCC, three clones; Daudi, two clones; MOLT-4, one clone), whereas the other six killed two different targets (ADCC and A1ab, one clone; K562 and MOLT-4, five clones). Clones derived from LGL preselected for positive reactivity with the monoclonal antibodies (MoAb) alpha OKM1, alpha OKT10 and alpha B73.1 also demonstrated either broad or restricted patterns of cytotoxicity. The LGL reactive with MoAb alpha B73.1 gave a high percentage of cytotoxic clones. Phenotype analysis showed that clones could express both antigens associated with T cells (i.e., OKT3, OKT4, and OKT8) and antigens shared by LGL (i.e., OKM1, OKT10, and B73.1). The pattern of surface markers varied considerably among the clones; however, no clear correlation between the pattern of antigenic phenotype and cytotoxic activity was seen. These data show that clones derives from purified preparations of LGL present different functional and antigenic characteristics, and support the hypothesis that the heterogeneity of the entire NK population is attributable, at least in part, to a mixture of clones that vary substantially in their target specificities and phenotypes.     

Hybridomas specific for carbohydrates; synthetic human blood group antigens for the production, selection, and characterization of monoclonal typing reagents

A general method for the production of carbohydrate-specific hybridoma antibodies is illustrated by generation of monoclonal antibody to the antigenic determinant of human blood group B. This trisaccharide determinant was chemically synthesized and covalently coupled to bovine serum albumin and human blood group O red cells. Soluble protein antigen and the 'artificial' B red cells were used to immunize BALB/c mice before fusion of spleen cells with the Sp2/0 plasmacytoma cell line. ELISA screening of putative hybrids for B-specific binding activity was facilitated by the availability of a second synthetic conjugate, B-horse hemoglobin. IgM-producing clones were identified by class-specific ELISA reagents and by hemagglutination assay. In this way, clones suitable for blood typing were rapidly identified. The precise antigenic specificity and Ig class of such monoclonal antibodies were defined by inhibition of precipitation and by gel filtration. Hybridoma antibodies were obtained from two separate fusion experiments. One of these, clone 3E-4, was of the IgM class and possessed a binding site that was completely satisfied (100% inhibition) by the trisaccharide determinant of the B blood group. This antibody is shown to be suitable for use in blood typing.     

Cell-surface associated proteins of corneal fibroblasts: dissection with monoclonal antibodies

It is now generally accepted that the cell surface is involved in the interaction of the cells with the extracellular matrix. To identify and characterize cell-surface-associated components of corneal fibroblasts, several monoclonal antibodies were developed. Hybridomas were developed by fusing mouse myeloma cells SP2/OAg14 with spleen cells from mice immunized with membrane fractions of corneal fibroblasts grown in culture. Twenty-five hybridomas secreting monoclonal antibodies to cell-surface components were selected by an enzyme-linked immunosorbent assay using corneal fibroblasts grown in microtiter plates as the substrate. Immunohistochemical staining demonstrated that the antigenic determinants recognized by these antibodies were not present on corneal epithelial cells, but were present on skin fibroblasts. The antigenic determinants recognized by two of these antibodies, designated 10D2 and 716, were matrix components of the corneal stroma. Immunochemical characterization of the antigens was carried out by indirect precipitation of the radioactively labeled cellular proteins with the monoclonal antibodies and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the precipitates. Four antibodies were able to precipitate antigens from cell extract in detectable amounts. Antibodies designated 5E2, 9G2, and 10D2 recognized antigens consisting of polypeptides of approximate molecular weights 105K and 110K, while antibody 716 recognized an antigen of 100K molecular weight. However, based on the tissue distribution and cell-surface distribution, these antibodies reacted with different antigenic determinants. The antigen recognized by 716 was also secreted by cells in culture but consisted of 220K and 200K polypeptide chains. It was tentatively identified as cellular fibronectin, based on the reaction of this antigen with polyclonal antibodies to plasma fibronectin.     

A coordinated cytotoxic effect of IFN-gamma and cross-reactive antibodies in the pathogenesis of Helicobacter pylori gastritis

Background. Helicobacter pylori (H. pylori) infection is associated with chronic infiltration into the stomach by T cells and plasma cells producing IFN‐γ and antibodies of various specificities, respectively. It is unknown whether these lymphocyte‐products may play coordinated roles in the gastric pathology of this infection. Aims. To know how IFN‐γ may relate to anti‐H. pylori antibodies in their roles in pathogenesis, we determined the isotype subclass of those antibodies as well as their cross‐reactivity and cytotoxicity to gastric epithelium. Methods and Results. We infected BALB/c mice with H. pylori (SS1, Sydney Strain 1) and generated monoclonal antibodies, which were comprised of 240 independent clones secreting immunoglobulin and included 80 clones reactive to SS1. Ninety percent of the SS1‐reactive clones had IgG2a isotype. Two clones, 2B10 and 1A9, were cross reactive to cell surface antigens in H. pylori and to antigens of 28 KDa and 42 KDa, respectively, which were present on the cell surface of and shared by both mouse and human gastric epithelial cells. The antigens recognized by these monoclonal antibodies localized a distinctive area in the gastric glands. In the presence of complement, 2B10 showed cytotoxicity to gastric epithelial cells. The effect was dose dependant and augmented by IFN‐γ. Finally, administration of 2B10 to mice with SS1 infection aggravated gastritis by increasing cellular infiltration. Conclusion. IFN‐γ by gastric T cells may participate in pathogenesis of the H. pylori infected stomach by directing an isotype‐switch of anti‐H. pylori antibodies to complement‐binding subclass and by augmenting cytotoxic activity of a certain autoantibody. This may explain a host‐dependent diversity in gastric pathology of the patients with H. pylori infection.     

Monoclonal antibodies against a human juxtaglomerular epithelioid granular cell tumour

With the exception of the renin-angiotensin system, the molecular composition of juxtaglomerular epithelioid granular cells (JEG cells) is unknown. We demonstrate the molecular peculiarities of these modified smooth muscle cells using monoclonal antibodies produced against a benign human JEG-cell tumour. Six out of 29 different clones produced antibodies that label JEG cells nearly exclusively. Antibodies from the other clones recognize JEG cells but also granularly or homogeneously distributed antigens of proximal tubule cells. This suggests antigenic similarity between granules of JEG cells and lysosomes of proximal tubule cells. Other clones produce antibodies which tag different cytoplasmic membranes or even mast cells. The antibodies directed exclusively against JEG cells promise to be useful tools to study their physiology and pathology.     

Reactivity of monoclonal islet cell antibodies on normal hyperplastic and neoplastic thyroid C-cells

Summary Thyroid C-cell reactivity to 15 monoclonal antibodies raised against a series of pancreatic islet cells (H[human]ISL, B[bovine]ISL and R[rat]ISL) was evaluated using an indirect immunoperoxidase technique on frozen thyroid sections. Of the monoclonal anti-islet cell antibodies, five reacted specifically with bovine C-cells or human hyperplastic and neoplastic C-cells but not with follicular cells. Two monoclonal antibodies of the bovine series showed strong immunoreactivity with C-cells and only a weakly positive immunostaining of follicular cells. Five monoclonal antibodies reacted with both thyroid C-cells and follicular cells, whereas 3 monoclonal anti-islet cell antibodies did not stain any cell type of the thyroid. In human medullary carcinomas, calcitonin- and somatostatin-producing neoplastic cells were immunoreactive with the same monoclonal antibodies as were normal human C-cells. The protein bands identified by the monoclonal antibodies in human medullary carcinomas had the same molecular weight as those from pancreatic islet extracts. Our study demonstrates the presence of similar differentiation antigens on thyroid C-cells and pancreatic islet cells; this further illustrates common modes of differentiation and specialisation of these embryologically different members of the dispersed neuroendocrine system. The crossreactivity of seven of the monoclonal antibodies investigated with follicular epithelium of the thyroid suggests the existence of common antigenic determinants in different endocrine organs and may partly explain the multiple organ autoimmune response found in patients with polyendocrine diseases.     

Murine/bovine hybridomas producing monoclonal alloantibodies to bovine red cell antigens

In attempts to produce stable lines secreting bovine monoclonal antibodies, murine/bovine hybridomas (1 degree xenohybridomas) were selectively cultured in 8-azaguanine to derive HAT-sensitive lines that were then used as myeloma partners for further fusions with bovine lymphocytes. The resulting 2 degrees xenohybridomas were further selected to produce 3 degrees xenohybridomas. Four stable lines secreting bovine monoclonal antibodies recognizing blood group determinants X1 (an IgG1), E'2 (an IgM) and SU" (an IgGI) and another (an IgGI) as yet unidentified were produced from fusions of 2 degrees xenohybridomas with lymphocytes from calves that had been immunized with bovine red cells.     

Theileria parva: bovine helper T cell clones specific for both infected lymphocytes and schizont membrane antigens

Two Theileria parva-specific bovine helper T cell clones were used to identify T. parva-derived antigens expressed on the surface of schizont infected lymphoblastoid cells. Although the clones proliferated in response to both the immunizing (Muguga) and heterologous stocks of T. parva, the patterns of the responses differed, showing that the two clones recognized different antigenic epitopes. Both clones were stimulated by autologous infected cells, without an additional source of antigen-presenting cells, as well as by purified schizonts and by a subcellular membrane fraction prepared from infected lymphoblastoid cells, when antigen-presenting cells were present. The membrane fraction was shown to be enriched for schizont membranes as indicated by the presence of a schizont surface antigen detected by immunoblotting using a schizont-specific monoclonal antibody. Elimination of schizonts with the anti-theilerial drug, parvaquone, resulted in reduced antigenicity of the membrane fraction as detected by both the T cell clones and the schizont-specific monoclonal antibody. We conclude that the T. parva-infected cell surface antigens recognized by the T cell clones are of schizont membrane origin. Although the antigens have not yet been characterized biochemically, the monoclonal antibody-specific epitope appears to be distinguishable from the T cell epitopes.     

Demonstration of two distinct antigenic determinants on hepatitis B e antigen by monoclonal antibodies

Mice were immunized against hepatitis B e antigen (HBeAg) isolated from sera of asymptomatic carriers of hepatitis B virus. Their spleen cells were fused with mouse myeloma (NS-1) cells, and 5 clones of hybridoma cells secreting antibody against HBeAg (anti-HBe) were isolated. For the production of anti-HBe in large scale, cells were cultivated both in vitro and in the peritoneal cavity of ascitic mice. Although monoclonal antibodies produced by these clones showed a strong reactivity of anti-HBe in hemagglutination tests, individual monoclonal anti-HBe did not reveal any precipitin line in immunodiffusion. When 2 of the 5 monoclonal antibodies were mixed together, however, some combinations showed a precipitin line against HBeAg, whereas others did not. Utilizing solid-phase radioimmunoassay involving a number of combinations of monoclonal antibodies used for solid-phase and radiolabeling, the 5 antibodies were classified into 2 groups. Three of the anti-HBe antibodies were found to be directed to 1 determinant of HBeAg (determinant a); the remaining 2 to the other determinant (determinant b). Determinants a and b were detected on HBeAg in the serum, as well as on the polypeptide of 19,000 daltons (P19) derived from the nucleocapsid of hepatitis B virus. Monoclonal anti-HBe antibodies with different specificities may provide useful tools in delineating the antigenic structure of HBeAg and also in evaluating immune responses of the host directed to its subdeterminants.     

Specific Schistosoma mansoni rat T cell clones. I. Generation and functional analysis in vitro and in vivo

In an attempt to determine the role of schistosome-specific T cells in the immune mechanisms developed during schistosomiasis, Schistosoma mansoni-specific T cells and clones were generated in vitro and some of their functions analyzed in vitro and in vivo in the fischer rat model. The data presented here can be summarized as follows: a) Lymph node cells (LNC) from rats primed with the excretory/secretory antigens-incubation products (IPSm) of adult worms proliferate in vitro only in response to the homologous schistosome antigens and not to unrelated antigens (Ag) such as ovalbumin (OVA) or Dipetalonema viteae and Fasciola hepatica parasite extracts. b) After in vitro restimulation of the primed LNC population with IPSm in the presence of antigen-presenting cells (APC) and maintenance in IL 2-containing medium, the frequency of IPSm-specific T cells is increased and the T cells can be restimulated only in the presence of APC possessing the same major histocompatibility complex (MHC) antigens. c) Following appropriate limiting dilution assays (LDA) (1 cell/well), 10 IPSm-specific T cell clones were obtained, and two of four maintained in culture were tested for their helper activity because they expressed only the W3/13+ W3/25+ surface phenotypes. d) The two highly proliferating IPSm-specific T cell clones (G5 and E23) exhibit an IPSm-dependent helper activity, as shown by the increase in IgG production by IPSm-primed B cells. e) IPSm-T cell clone (G5) as well as IPSm-T cell lines when injected in S. mansoni-infested rats can exert an in vivo helper activity, which is characterized by an accelerated production of IgG antibodies specific for the previously identified 30 to 40 kilodaltons (kd) schistosomula surface antigens (Ag). As recent studies have demonstrated that rat monoclonal antibodies recognize some incubation products of adult S. mansoni as well as one of the 30 to 40 kd schistosomula surface antigens, and taking into account the fact that the T cell clones here studied were restimulated either with IPSm or with schistosomulum Ag, it appears that such IPSm-specific T cell clones could be involved in the concomitant immunity mechanisms.     

Differentiation antigens in human T-cell activation: Evidence that anti-VH antibodies react with a membrane structure on human T Lymphocytes distinct from the antigens detected by monoclonal antibodies of the OKT and Leu series

The effect of a panel of monoclonal antibodies and heteroantibodies on T-cell proliferation in various assay systems has been examined. The antibodies tested were directed against T-cell differentiation antigens, HLA-DR antigens, and structures defined by an anti-human V_H antiserum. As the test cell system highly purified subpopulations of T-cell growth factor (TCGF)-dependent T-cell lines activated either by mitogen or antigen were used. A survey of the data indicates the following: (1) Mitogenic and antigenic triggering of T lymphocytes are mediated through partly different membrane structures. (2) Antigenic stimulation by purified protein derivative (PPD) as well as polyclonal activation induced by OKT3/anti-Leu 4 monoclonal antibodies can be inhibited by heteroantibodies raised against human immunoglobulin V_H fragments thus pointing to a possible connection between the antigens detected by these antisera. (3) There does not seem to be differences between the two major subpopulations of T lymphocytes (i.e., helper/inducer and suppressor/cytotoxic cells) as to how they respond to antigens or mitogens in the investigated assay systems. (4) A clear distinction was found between T blasts specific for PPD and allogeneic cells as compared to cytotoxic T cells (CTL), as the T4 and T8 antigens seem to be functionally important for antigen recognition among CTL but not for the blasts proliferating in response to PPD and allogeneic cells. (5) An inhibitory effect of OKT3/anti-Leu 4, OKIal, and anti-HLA-DR on TCGF-dependent growth was detected, possibly indicating a steric relationship between these antigens and TCGF receptors on mitogen-induced T blasts. (6) Soluble factors obtained after incubating adherent cells with OKIal and anti-HLA-DR antibodies seemed to have an inhibitory effect on overall T-cell proliferation stressing the importance of studying the T-cell activation process at different levels in these kinds of experiments. (7) The results further suggest a complexity in the build up of antigen receptors on the various T-effector cells, perhaps also involving receptors for growth factors, HLA-DR antigens, and receptors for the latter.     

Further evidence against random polyclonal antibody formation in mice with lupus-like graft-vs-host disease

The pathologic symptoms in F1 mice with chronic graft-vs-host disease (GVHD) (GVH F1) strongly resemble those of systemic lupus erythematosus (SLE). Mice with SLE-like GVHD do not produce antibodies to a number of non-self and self antigens. This finding is inconsistent with the widely accepted view that the (auto)-antibody formation in SLE is polyclonal in the sense that B cells are triggered at random, i.e., irrespective of their specificity. In the present study, therefore, we performed a systematic study of the kinetics of total IgM- and IgG-secreting splenic B cells and tested their specificities. The total IgM-secreting B cell population was increased only in the first week after the initiation of SLE-like GVHD; it seemed to reflect a random, but self-limited, polyclonal B cell stimulation. In contrast, the total number of IgG-secreting cells in the GVH F1 mice was increased to a much higher extent than that of the IgM-secreting cells and remained increased. At no time during GVHD was there an increase in the number of plaque-forming cells (PFC) spontaneously secreting IgG antibodies to non-self antigens. The GVH reaction (GVHR) did, however, lead to the appearance of PFC that secreted IgG antibodies to DNA. Similarly, the GVH F1 mice showed high serum titers of antibodies to self antigens characteristic of SLE and to endogenous viruses, but during the entire observation period they failed to develop serum antibodies to non-self antigens and insulin. Hence, the enhanced production of Ig, especially that of IgG, that occurs in SLE-like GVHD is not a random process, because it requires the presence of antigen, or signal 1. The data support our hypothesis that only certain kinds of self antigen, such as DNA and cell membrane epitopes, can cross-link the Ig receptors on the corresponding B cells and thus provide an adequate signal 1. Given the increase in help, or signal 2, in chronic GVHD, only the B cell clones that simultaneously receive an adequate signal 1 seem to be driven into clonal proliferation and IgG secretion.     

Taenia saginata: Production and characterization of monoclonal antibodies against Taenia saginata metacestode antigens

Cysticercosis is a major cause of economic loss in bovine production due to meat condemnation. Chemotherapy is being used in Brazilian cattle and a diagnostic test to improve the treatment program is desired. We produced monoclonal antibodies against crude (TAEB) and cyst fluid (TAEF) Taenia saginata metacestode antigens using immunized BALB/c mice. After cell fusion, 10 TAEB and nine TAEF hybrids were selected and cloned resulting in 18 IgG₁ and 32 IgM TAEB clones, and 9 IgG₁ and 9 IgM TAEF clones. Ascites was produced and Western blot testing was performed resulting in reactivity to protein fractions of low molecular weight (<18 kDa), 43, 55, 66 and 100 kDa. The indirect immunofluorescence test, with one monoclonal antibody against crude and one against cyst fluid antigens, recognized antigenic fractions of both the scolex and the bladder wall of metacestodes from naturally infected bovine.     

Antigenic determinants shared between HLA-A, −B, −C antigens and H-2 class I molecules modified by bovine beta-2 microglobulin

The specificity of the mouse class I-specific antibody COB6-3 was examined in detail. It was found to react with the mouse class I molecules H-2D^b, K^d, and Qa-2, and with human HLA-A, –B, –C antigens. The specificity pattern of COB6-3, despite its different origin, was similar to that of the monomorphic HLA class I-specific antibody W6/32. Cross-inhibition studies show that on human cells the antigenic determinants recognized by the two antibodies are situated close together and may be identical. On mouse cells, reactivity of both antibodies was generated upon replacement of mouse beta-2 microglobulin (B2m) with its bovine counterpart, but differences in specificity were observed using human B2m.Abbreviations used in this paper B2m beta-2 microglobulin - BSA bovine serum albumin - FCS fetal calf serum - FITC fluorescein isothiocyanate - MHC major histocompatibility complex - PBL peripheral blood lymphocytes - PBS phosphate-buffered saline - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis     

Determination of antigenic domain in GST fused major surface protein (Nc-p43) of Neospora caninum

The antigenic domain of the major surface protein (Nc-p43) of Neospora caninum was examined by polymerase chain reaction of its gene fragments and recombinant expression as GST fusion proteins. The fragments of Nc-p43 were as follow: a total open reading frame (OFR), T; OFR without signal sequence and C-terminal hydrophobic sequence, S; N-terminal 2/3 parts of S, A; C-terminal 2/3 parts, P; N-terminal 1/3 part, X; middle 1/3 part, Y; and C-terminal 1/3 part, Z, respectively. The DNA fragments were cloned into pGEX-4T vector. Recombinant plasmids transformed into Escherichia coli of BL21 pLysS (DE3) strain were induced to express GST or GST fused fragments of Nc-p43 such as 69 kDa protein for T, 66 kDa for S, 52 kDa for A, 53 kDa for P, and 40 kDa proteins for X, Y, and Z, respectively in SDS-PAGE. The Nc-p43 fragments of T, S, and P reacted with a bovine serum of neosporosis while those of A, X, Y, and Z together with GST did not in the western blot. These findings suggest that the antigenic domain of Nc-p43 of N. caninum may be localized in the C-terminal 2/3 parts. Together with A19 clone in SAG1 of Toxoplasma gondii (Nam et al., 1996), the P fragment of Nc-p43 could be used as efficient antigens to diagnose and differentiate those infections with both species.