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Verzili D, Citro G, Ascoli F, Chiancone E. Immunological properties of the dimeric and tetrameric hemoglobins from the mollusc Scapharca inaequivalvis. FEBS Lett 2001. [DOI: 10.1016/0014-5793(85)80290-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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2
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Blank VC, Peña C, Roguin LP. Suitable experimental conditions are required to characterize interferon-alpha2b synthetic peptides. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5711-6. [PMID: 10971581 DOI: 10.1046/j.1432-1327.2000.01618.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The binding and antiproliferative activities of synthetic peptides 29-35 and 122-139 of interferon-alpha2b, both of which contain a cysteine residue in their sequences, were studied in the presence or absence of a dissociation medium containing mainly urea, dithiothreitol and 2-mercaptoethanol. Although interferon-alpha2b peptides either did not modify or slightly increased 125I-labelled interferon-alpha2b specific binding to WISH cell-membrane receptors in the absence of dissociation medium, significant binding inhibition was obtained when both peptides were assayed in dissociation medium. Furthermore, also in the presence of dissociating agents, the two fragments inhibited cell growth in a concentration-dependent manner, the 122-139 sequence being more effective than the 29-35 sequence. No additive effect on interferon binding and cell proliferation was observed when both peptides were added simultaneously. Results obtained after submitting peptide 122-139 to gel filtration or PAGE under different experimental conditions showed the presence of dimers and/or noncovalent aggregates arising from intermolecular disulfide bridges or hydrophobic interactions. Thus, our results indicated that peptide effects on 125I-labelled interferon-alpha2b binding and WISH cell proliferation were clearly manifested when the amount of monomeric species increased, showing that suitable experimental conditions should be used to study peptide behavior. The ability of both peptides to effectively trigger an interferon-specific biological action, such as cell growth inhibition, strongly suggested that 29-35 and 122-139 interferon-alpha2b fragments constitute the conformational epitope or mimotope that interacts with the cytokine-specific receptor.
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Affiliation(s)
- V C Blank
- Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina
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3
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Molecular dissection of protein antigens and the prediction of epitopes. SYNTHETIC PEPTIDES AS ANTIGENTS 1999. [DOI: 10.1016/s0075-7535(08)70446-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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4
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Loomans EE, Gribnau TC, Bloemers HP, Schielen WJ. Adsorption studies of tritium-labeled peptides on polystyrene surfaces. J Immunol Methods 1998; 221:131-9. [PMID: 9894904 DOI: 10.1016/s0022-1759(98)00174-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this study, three presentation formats of an epitope peptide (hepta-peptide), derived from the human chorionic gonadotropin amino acid sequence, were compared for adsorption to the polystyrene wells of a microELISA plate. The peptides had either a free N-terminus, an Ata-group or a linear (Lys)7-extension at the N-terminal. In order to measure the adsorption properties, all peptides were tritiated by synthesizing an additional 3H-labeled glycyl residue to the N-terminus of their peptide sequence. Over a broad range of peptide concentrations used as coat solution, extension of the peptide by an Ata-group consistently increased adsorption by a factor of 1.5 to 3 compared to the free parent peptide. Of the three peptides studied, the Ata-peptide showed the highest surface coverage of 0.6 mg/m2 when 1.0 mmol/l was offered as the concentration of peptide in the coating solution. The highest surface coverage observed for the parent peptide was 0.4 mg/m2 (at 1.5 mmol/l). The lysyl (K7) peptide showed a maximum plateau value of 0.2 mg/m2, and therefore the lysyl (K7) extension reduced the peptide surface coverage at relatively high coat concentrations (above 0.1 mmol/l) compared to the parent peptide. At lower input concentrations (below 0.1 micromol/l), however, the packing density of the lysyl (K7) peptide was up to 25 times higher when compared to the other two peptide analogs. We conclude that better adsorption as well as improved antibody binding activity and (functional) affinity could explain the higher reactivity observed in ELISA procedures when peptides are N-terminally extended by an Ata-group or lysyl (K7) extension.
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Affiliation(s)
- E E Loomans
- ATO-DLO, Department of Industrial Proteins, Wageningen, The Netherlands
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5
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Yiannaki EE, Tzioufas AG, Bachmann M, Hantoumi J, Tsikaris V, Sakarellos-Daitsiotis M, Sakarellos C, Moutsopoulos HM. The value of synthetic linear epitope analogues of La/SSB for the detection of autoantibodies to La/SSB; specificity, sensitivity and comparison of methods. Clin Exp Immunol 1998; 112:152-8. [PMID: 9566804 PMCID: PMC1904932 DOI: 10.1046/j.1365-2249.1998.00558.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/1997] [Indexed: 02/07/2023] Open
Abstract
In a previous study it was shown that La/SSB contains four linear epitopes, p147-154, p291-302, p301-318 and p349-364. The aim of the present study was to investigate the value of the synthetic epitope analogues of the La/SSB autoantigen for the detection of antibodies to La/SSB, in comparison with recombinant La and fragments of this protein. A total of 122 sera with anti-La/SSB activity, from patients with primary Sjögren's syndrome (pSS) or systemic lupus erythematosus (SLE), were tested in various peptide-based assays. In addition, 62 sera from pSS or SLE patients with other autoantibody specificities and 95 sera from healthy individuals were used as controls. The autoantibody specificity was identified by counter immunoelectrophoresis and immunoblot. The peptide-based ELISA assays presented sensitivities ranging from 78% to 88-8% and specificities from 69% to 94-3%. Dot blot assays exhibited sensitivities ranging from 93-6% to 97%, but remarkably lower specificities from 56% to 88%. The most sensitive and specific peptide 349GSGKGKVQFQGKKTKF364 was synthesized and attached on a tetramer sequential oligopeptide carrier SOC4 and used for immunoassay development. Assays based on the recombinant native La protein, the La-C terminal (215 aa), and the N-terminal of La with a mutation at base pair 640 (nine adenines instead of eight) were also developed and compared with the SOC4 peptide-based assay. Of anti-La-positive sera, 88.1% were reactive with both the synthetic peptide SOC4-(349-364aa) and the recombinant La protein. Eighty-three percent of sera were reactive with the La N-terminus and 67.8% of sera were reactive with the La C-terminus. Using sera that were anti-Ro-positive but anti-La-negative, 37% were reactive with the recombinant protein, 26% with the La N-terminus, 33% with the La C-terminus and only 11 % with the synthetic peptide. Our results suggest that the synthetic peptide epitopes exhibit high sensitivity and specificity for the detection of anti-La/ SSB antibodies in ELISA and dot blot techniques. The peptide SOC4-(349-364aa) has the same sensitivity for the detection of anti-La/SSB antibodies as the recombinant protein.
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Affiliation(s)
- E E Yiannaki
- Department of Pathophysiology, National University of Athens, Greece
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6
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Yao ZJ, Chan MC, Kao MC, Chung MC. Linear epitopes of sperm whale myoglobin identified by polyclonal antibody screening of random peptide library. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1996; 48:477-85. [PMID: 8956081 DOI: 10.1111/j.1399-3011.1996.tb00866.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Distinct enhancement of antibody-specific clones was apparent during the screening against random peptide libraries with antigen-specific polyclonal antibodies. Several sequence motifs obtained from these screenings were homologous with the primary sequence of myoglobin. Two of these motifs have been confirmed as antigenic determinants by competitive inhibition tests using eight-branched synthetic peptides. One of the peptides has a sequence that corresponds to amino acid residues 42-50, KFDRFKHLK, of the myoglobin sequence. This is a new epitope of myoglobin that is reported for the first time. The epitope is located precisely in the "turn' or "loop' region between helices C and D of the crystal structure of myoglobin. The second antibody binding site has a sequence of DIAAKYKELGYQG, and this is located between residues 141-153, which is the C-terminus of myoglobin. This epitope encompassed two linear epitopes of myoglobin, amino acid residues 145-151 and 147-153, that have been reported earlier based on immunochemical characterisation of cleavage fragments of the protein. These results clearly indicate that epitope mapping using polyclonal antibodies against random peptide libraries can identify new epitopes precisely, as well as confirm epitopes of myoglobin obtained earlier using established methodologies.
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Affiliation(s)
- Z J Yao
- Bioprocessing Technology Centre, National University of Singapore, Republic of Singapore
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7
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Levieux D, Levieux A. Antigenic specificity of monoclonal antibodies to beef myoglobin determined by cross-reactivity studies against myoglobins from domestic species. Meat Sci 1996; 42:239-49. [DOI: 10.1016/0309-1740(95)00056-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/1995] [Revised: 09/04/1995] [Accepted: 09/18/1995] [Indexed: 10/18/2022]
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8
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Galperin C, Leung PS, Gershwin ME. Molecular biology of autoantigens in rheumatic diseases. Rheum Dis Clin North Am 1996; 22:175-210. [PMID: 8907071 DOI: 10.1016/s0889-857x(05)70268-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The advent of molecular biologic techniques has provided new approaches that are of great utility to the study of autoimmune-mediated responses. In the past few years, there has been a remarkable accumulation of knowledge concerning the molecular identity and function of autoantigens, and further consolidation for the use of autoantibodies as diagnostic markers in clinical rheumatology. The understanding of basis methodologies in molecular biology applied to the study of autoantigens, in particular, techniques for cloning and analyzing genes that are important in rheumatic diseases, is valuable for both basic scientists and clinicians interested in diagnostic and prognostic markers of various connective tissue diseases.
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Affiliation(s)
- C Galperin
- University of California, Davis, School of Medicine, USA
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9
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Oshima M, Nakamura S, Atassi MZ. Amino acid substitutions outside a preselected antigenic region in hemoglobin affect the binding to monoclonal antibodies obtained by immunization with the synthetic region. JOURNAL OF PROTEIN CHEMISTRY 1993; 12:403-12. [PMID: 8251060 DOI: 10.1007/bf01025040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
It is often assumed that amino acid substitutions outside a protein antigenic site have no effect on the reactivity of a protein variant with antibodies, especially monoclonal antibodies (mAbs). Substitutions that exert an effect on the reactivity of a protein variant with mAbs are frequently considered to be within the antigenic site of the mAb. To test this assumption, two mAbs [IgG1(k) and IgG2a(k)] were prepared by immunization with a synthetic peptide corresponding to region 63-78 of the alpha chain of human hemoglobin (Hb). The peptide was used as an immunogen in its free form (i.e., without conjugation to a carrier), so that the results will not be made ambiguous by peptide modification nor by an immune response to sites spanning peptide and protein carrier. In addition to their reaction with human Hb, the mAbs were also studied with four primate Hbs which had no substitutions within region alpha 63-78 and only a limited number of substitutions which occurred outside of, and at considerable distances in three-dimensional (3D) structure from, this region. Inhibition studies revealed substantial differences in the binding affinities of some of the primate Hbs, relative to human Hb. Some of the substitutions caused major decreases in binding, although they were at considerable distances in the 3D structure from the indicated site residues. It is concluded that substitutions in a protein, even when distant from an antigenic site, can exert major influences on the protein's reactivity with anti-site mAbs.
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Affiliation(s)
- M Oshima
- Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030
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10
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Abaza MS, Atassi MZ. Effects of amino acid substitutions outside an antigenic site on protein binding to monoclonal antibodies of predetermined specificity obtained by peptide immunization: demonstration with region 113-120 (antigenic site 4) of myoglobin. JOURNAL OF PROTEIN CHEMISTRY 1992; 11:677-86. [PMID: 1281636 DOI: 10.1007/bf01024969] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Immunochemical cross-reactivity of protein variants has been very frequently used to map protein antigenic sites. The approach is based on the assumption that amino acid substitutions affecting the binding of a protein to its antibody, particularly when monoclonal antibodies (mAbs) are used, must be part of the antigenic site and not far from it. The assumption was investigated in this study by determining the effects of amino acid substitutions outside the antigenic site on the reactivity of six myoglobin (Mb) variants with three mAbs of predetermined specificity prepared by immunization with a free synthetic peptide representing region 113-120 (antigenic site 4) of Mb. Two of the Mb variants used had no substitutions within residues 113-120 (the region to which the specificity of the mAbs is directed) and yet exhibited markedly decreased cross-reactions and binding affinities, relative to the reference antigen, sperm-whale Mb. The other three Mb variants possessed substitutions within, as well as outside, region 113-120 and showed very little cross-reactivities. The results of this study, particularly with the Mbs that have no substitutions within the indicated antigenic site, clearly show that substitutions outside the site, and which by design are not part of the site, can influence very markedly the reactivity of the protein variant with the anti-site mAbs. The approach can, therefore, lead to serious errors if used to identify residues of protein antigenic sites.
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Affiliation(s)
- M S Abaza
- Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030
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11
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Abaza MS, Atassi MZ. Effects of amino acid substitutions outside an antigenic site on protein binding to monoclonal antibodies of predetermined specificity obtained by peptide immunization: demonstration with region 94-100 (antigenic site 3) of myoglobin. JOURNAL OF PROTEIN CHEMISTRY 1992; 11:433-44. [PMID: 1280436 DOI: 10.1007/bf01025020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Amino acid substitutions outside protein antigenic sites are very frequently assumed to exert no effect on binding to antiprotein antibodies, especially if these are monoclonal antibodies (mAbs). In fact, a very popular method for localization of residues in protein antigenic sites is based on the interpretation that whenever a replacement causes a change in binding to antibody, then that residue will be located in the antigenic site. To test this assumption, mAbs of predetermined specificity were prepared by immunization with a free (i.e., without coupling to any carrier) synthetic peptide representing region 94-100 of sperm whale myoglobin (Mb). The cross-reactivities and relative affinities of three mAbs with eight Mb variants were studied. Five Mb variants which had no substitutions within the boundaries of the designed antigenic site exhibited remarkable, and in two cases almost complete, loss in cross-reactivity relative to the reference antigen, sperm whale Mb. Two myoglobins, each of which had one substitution within region 94-100, showed little or no reactivity with the three mAbs. It is concluded that substitutions outside an antigenic site can exert drastic effects on the reactivity of a protein with mAbs against the site and that caution should be exercised in interpreting cross-reactivity data of proteins to implicate residues directly in an antigenic site.
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Affiliation(s)
- M S Abaza
- Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030
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12
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Abstract
The rapid progress made over the last 10 years in the identification of individual autoantigens and in the localization of the epitopes involved, has resulted in a parallel reduction in the complexity of the antigen required for the detection of autoantibodies. The ability to use synthetic peptides as antigens is a remarkable culmination of this process considering that many antigenic particles contain multiple proteins (eg. Sm consist of 8 or more individual proteins). Despite the fact that patients with SLE have a polyclonal hypergammaglobulinemia, excellent correlations between ELISAs utilizing the P2 or SmB/B' synthetic peptides, ELISAs utilizing r proteins and immunoblotting were obtained [28, 38, 50]. However, false positive/non-specific binding to a P2-BSA-glutaraldehyde conjugate has been observed with serum from old MRL/lpr mice (unpublished observations). In addition, some of the results obtained in human autoimmune diseases suggest that non-specific binding may be problematic in some instances. It is difficult, at present, to know whether the higher frequencies of detection of autoantibodies to certain synthetic peptide antigens reflect increased sensitivity or decreased specificity. Synthetic peptide antigens have been used to detect autoantibodies in both organ specific and multisystem autoimmune diseases. In only a small number of cases have these reagents been rigorously tested for sensitivity and specificity. Despite this, synthetic peptides have been shown to be valuable for detection and quantification of autoantibodies in certain clinical situations. Undoubtedly, further progress in epitope mapping of autoantigens coupled with technological advances in protein synthesis and improved prediction of protein structure will lead to a large number of synthetic peptide antigens for research and clinical applications.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K B Elkon
- Hospital for Special Surgery-Cornell University Medical College, New York, NY 10021
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13
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Larvor MP, Djavadi-Ohaniance L, Friguet B, Baleux F, Goldberg ME. Peptide/antibody recognition: synthetic peptides derived from the E. coli tryptophan synthase beta 2 subunit interact with high affinity with an anti-beta 2 monoclonal antibody. Mol Immunol 1991; 28:523-31. [PMID: 2062325 DOI: 10.1016/0161-5890(91)90167-i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Recent studies have shown that the antigenic determinant recognized by a monoclonal antibody (mAb 164-2) elicited against the beta 2 subunit of E. coli tryptophan synthase is localized between residues 276 and 297 of this protein. In order to delineate more precisely the epitope recognized by this antibody, peptides ranging in length from 11 to 29 amino acids and belonging to this region were synthesized, and their interactions with the antibody are described in this paper. The smallest peptide recognized with a high affinity by antibody 164-2 contains 11 residues (273-283). This peptide is recognized by antibody 164-2 with an affinity (KD = 7.5 x 10(-9) M) very close to that of the native beta 2 subunit, suggesting a high structural similarity of the epitope inside the protein and in the isolated peptide. The corresponding sequence of beta 2 is located in a region protruding from the protein surface that contains a beta-turn as unique element of secondary structure in the crystallographic model. The absence of interaction between antibody 164-2 and the octapeptide lacking the three residues at the C-terminal end of peptide 11 suggests that the beta-turn is important in the recognition by the antibody. Kinetic studies were performed to find out whether or not the binding of the antibody to the peptide involves any conformational adaptation. The dissociation equilibrium constant (KD), the dissociation rate constant (koff) and the association rate constant (kon) were measured for eight peptide/antibody complexes. The values obtained were compatible with a one-step reaction, suggesting that no important conformational adaptation is involved in the formation of the peptide/antibody complexes. Furthermore, it has been shown that differences in affinity of antibody 164-2 for the various peptides were mainly due to differences in the dissociation rate constants (koff) and not in the association rate constants (kon). The exceptional location of the epitope in the native protein and the unusually high affinity of the 11-residue peptide for mAb 164-2, makes this peptide a good model for studying the interaction between an antibody and a continuous epitope of a protein.
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Affiliation(s)
- M P Larvor
- Unité de Biochimie Cellulaire, Institut Pasteur, Paris, France
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14
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Hodder A, Machin K, Aguilar M, Hearn M. High-performance liquid chromatography of amino acids, peptides and proteins. J Chromatogr A 1990. [DOI: 10.1016/s0021-9673(01)84178-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Quesniaux VF, Schmitter D, Schreier MH, Van Regenmortel MH. Monoclonal antibodies to cyclosporin are representative of the major antibody populations present in antisera of immunized mice. Mol Immunol 1990; 27:227-36. [PMID: 2342487 DOI: 10.1016/0161-5890(90)90134-l] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Two series of mouse antisera raised against cyclosporin (Cs)-carrier conjugates exposing opposite sides of the Cs molecule and more than sixty monoclonal antibodies (mAbs) derived from the same animals were compared in terms of isotype and fine specificity for Cs. The predominant isotypes of the mAbs reflected the in situ distribution of the circulating anti Cs antibodies. The fine specificity of the antibodies was studied by determining their cross-reactivity for a series of Cs-derivatives and Cs-metabolites in competitive ELISA. The antisera raised by different immunizations showed very different cross-reactivity patterns for the Cs-derivatives. However, the in situ anti Cs antibody populations and the majority of mAbs derived from the corresponding animals showed a striking similarity in fine specificity for restricted clusters of residues on the Cs molecule. These results indicate that the mAbs produced against Cs are representative of the major antibody population present in the sera of the mice used for the fusion. By determining the characteristics of antibodies found in the serum of immunized mice it may thus be possible to select animals that are likely to give rise to mAbs of a certain isotype and specificity.
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Affiliation(s)
- V F Quesniaux
- Preclinical Research, Sandoz Ltd., Basel, Switzerland
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16
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Mollerach-Gobbi B, Retegui LA, Peña C. Equine growth hormone. Detection of immunoreactive sequences using poly- and monoclonal antibodies. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1990; 35:105-10. [PMID: 1691154 DOI: 10.1111/j.1399-3011.1990.tb00243.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The immunochemical behavior of several fragments of equine growth hormone (eGH) was examined using competitive binding assays with antibodies (Abs) to eGH obtained from different sources. Antigenicity was detected within the sequences 5-72 and 73-123 by rabbit Abs to eGH and by three mouse monoclonal antibodies (MAbs) produced by using bovine growth hormone as immunogen, but showing heteroclitic properties towards eGH. The polyclonal Abs to eGH also recognized as immunoreactive two smaller peptides corresponding to the amino acid residues 52-72 and 110-123. By contrast, the heteroclitic Abs to eGH developed by hypopituitary patients therapeutically injected with human growth hormone failed to react with any eGH-derived fragment. The rabbit polyclonal Abs and the mouse MAbs scarely discriminated between native and S-carbamidomethylated eGH, while the heteroclitic human Abs detected a clear difference between the native and the modified hormone.
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Affiliation(s)
- B Mollerach-Gobbi
- Institute of Chemistry and Biophysics (UBA-CONICET), Faculty of Pharmacy and Biochemistry, Buenos Aires, Argentina
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17
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Bahraoui E, Clerget-Raslain B, Granier C, Van Rietschoten J, Sabatier JM, Labbé-Julie C, Ceard B, Rochat H, Gluckman JC, Montagnier L. Accessibility of the highly conserved amino- and carboxy-terminal regions from HIV-1 external envelope glycoproteins. AIDS Res Hum Retroviruses 1989; 5:451-63. [PMID: 2548546 DOI: 10.1089/aid.1989.5.451] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Amino- and carboxy-terminal extremities of the envelope external glycoproteins are regions that have remained highly conserved between human immunodeficiency viruses HIV-1 and HIV-2. The corresponding peptides have been synthesized and their structure and function analyzed. Circular dichroism spectra showed evidence of alpha helical conformation when the peptides were dissolved in the nonpolar solvent trifuoroethanol. These two regions are indeed exposed on the molecule because they were accessible to their respective specific antibodies on the native gp160 precursor or processed gp120 glycoproteins of HIV-1. Neither the peptides nor rabbit or human antibodies directed against the N- and C-terminal peptides interfered with the interaction between HIV-1 external glycoprotein gp120 and its CD4 cellular receptor. Taken together, these results indicate that N- and C-terminal regions of gp120 are accessible on the quaternary structure of the virion as well as on the soluble form of gp120 and that these regions are not directly or indirectly involved in the binding of gp120 to CD4.
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Affiliation(s)
- E Bahraoui
- Unité d'Oncologie Virale, Institut Pasteur, Paris, France
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18
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Affiliation(s)
- D R Milich
- Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, California 92037
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19
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Abstract
Antigen valency has been defined (Singer, 1965) as the maximum number of epitopes per antigen which can be simultaneously occupied by antibody. If the epitopes are closely spaced, steric hindrance prevents the simultaneous occupancy of all epitopes. Current methods of estimating both the antigen valency and the association constant (Ka) from equilibrium binding data do not allow for the effects of steric hindrance. We have developed a theory which accounts rigorously for steric hindrance when monovalent ligands of quite general shape (antibodies) react reversibly with multivalent acceptor molecules (antigens). The surfaces of the acceptors are modelled by completely general two-dimensional lattices. Using this theory we demonstrate that curvature of Scatchard plots can arise from steric effects alone in the absence of other known causes such as cross-linking, cooperativity and heterogeneous epitope affinities. Our results generalize the conclusions of McGhee & von Hippel (1974) who dealt with one-dimension acceptor molecules such as DNA. We discuss inaccuracies in the estimation of both Ka and antigen valency using the traditional approach of fitting straight lines to Scatchard plots.
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Affiliation(s)
- R Cowan
- CSIRO Division of Mathematics and Statistics, Lindfield, NSW, Australia
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20
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Van Regenmortel MH, Daney de Marcillac G. An assessment of prediction methods for locating continuous epitopes in proteins. Immunol Lett 1988; 17:95-107. [PMID: 2452136 DOI: 10.1016/0165-2478(88)90076-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Many attempts have been made to predict the position of antigenic sites in proteins from certain features of their primary structure. Parameters such as the hydrophilicity, static accessibility and mobility of short segments of polypeptide chains have been correlated with the location of continuous epitopes in proteins. Relative scales describing the structural propensity of each of the 20 amino acids have been derived and these are commonly used for constructing structural prediction profiles and for locating the position of epitopes. The predictive value of algorithms based on eight such scales has been compared in the present study, using as antigenicity data base the location of 29 continuous epitopes in four model proteins. A chi 2 statistical analysis showed that a segmental mobility scale and a hydrophilicity scale based on peptide retention times during chromatography gave the highest level of correct predictions.
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Affiliation(s)
- M H Van Regenmortel
- Laboratoire d'Immunochimie, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
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21
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Jaegle M, Briand JP, Burckard J, Van Regenmortel MH. Accessibility of three continuous epitopes in tomato bushy stunt virus. ANNALES DE L'INSTITUT PASTEUR. VIROLOGY 1988; 139:39-50. [PMID: 3207502 DOI: 10.1016/s0769-2617(88)80004-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Three peptides corresponding to residues 28-40, 138-154 and 380-387 of the coat protein of tomato bushy stunt virus (TBSV) were synthesized by the solid phase method and used to raise specific antibodies. These antibodies were used to follow the conformational changes that occur when TBSV particles swell under slightly alkaline conditions. Peptides 28-40 and 380-387 were found to correspond to continuous epitopes in the dissociated viral protein as well as in both compact and swollen virions. The region 138-154, which is also a continuous epitope of the monomeric protein, became accessible to antibody binding in the virion only when the particles were in the swollen state.
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Affiliation(s)
- M Jaegle
- Laboratoire d'Immunochimie, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
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22
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Conrad U, Walter G, Helbing D, Manteuffel R, Schöneich J. Immunochemical differentiation of glucose phosphate isomerase (GPI) allozymes of the mouse. Biochem Genet 1987; 25:739-54. [PMID: 3325033 DOI: 10.1007/bf00556216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Polyclonal xenoantisera against mouse GPI-1B and GPI-1C were produced in rabbits and analyzed for their ability to recognize allozyme-specific determinants. These studies showed a high degree of serological similarity among the three allozymes of mouse glucose phosphate isomerase (GPI). However, GPI-1B and GPI-1C could be differentiated from GPI-1A as well as GPI-1A and GPI-1B from GPI-1C using quantitative solid-phase immunobinding assays. In addition, polyclonal and monoclonal alloantibodies specific for GPI-1C were produced in BALB/c (Gpi-1a/Gpi-1a) mice. As indicated by immunoblotting data, the allozyme specificity of rabbit antisera and monoclonal alloantibodies against GPI-1C is dependent on the native structure of that allozyme.
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Affiliation(s)
- U Conrad
- Zentralinstitut für Genetik und Kulturpflanzenforschung der AdW der DDR, Gatersleben, German Democratic Republic
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23
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Bahraoui E, el Ayeb M, Granier C, Rochat H. Immunochemistry of scorpion toxins. Immunogenicity of peptide 19-28 a model of an accessible and relatively rigid region. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 167:371-5. [PMID: 2441989 DOI: 10.1111/j.1432-1033.1987.tb13347.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Peptide 19-28, a model of an antigenic region of Androctonus australis Hector toxin II, has a rigid alpha-helix structure in the native protein. It was used as immunogen either in the free form, or bound to bovine serum albumin (BSA) or linked to its synthesis support (macroporous polyacrylamide resin). Only the anti-(peptide-BSA) and the anti-(peptide-resin) antibodies recognized the native toxin. The use of short synthetic analogues of peptide 19-28 suggests a specificity difference in the two antipeptides. Anti-(peptide-BSA) recognizes probably two determinants localized at the C and N terminals of the peptide chain. Anti-(peptide-resin) preferentially recognizes the N-terminal extremity. Finally we showed that the alpha-helix region remains accessible to antipeptide 19-28 when the toxin is bound to its receptor.
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24
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Krchnák V, Mach O, Malý A. Computer prediction of potential immunogenic determinants from protein amino acid sequence. Anal Biochem 1987; 165:200-7. [PMID: 2446525 DOI: 10.1016/0003-2697(87)90220-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In proteins, immunogenic determinants that can induce protein-reactive antipeptide antibodies reside mostly in those parts of the molecule that have a high tendency to form beta-turns. A program for an IBM personal computer which predicts protein immunogenic determinants is described. The program predicts potential immunogenic determinants from protein amino acid sequences according to a Chou-Fasman-based probability of a beta-turn occurrence, p greater than 1.5 X 10(-4)(P. Y. Chou and G. D. Fasman, 1978, Adv. Enzymol. 47, 46-148). Oncopeptides (whose efficacy in generating protein-reactive antipeptide antibodies has been described) with a beta-turn probability of p greater than 1.5 X 10(-4) elicited antipeptide antibodies that reacted with the parent oncoprotein at a rate of 96%, thus showing a surprisingly good correlation between the tendency to form a beta-turn and the protein reactivity of antipeptide antibodies. Potential immunogenic determinants were predicted on myohemerythrin and myoglobin.
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Affiliation(s)
- V Krchnák
- Léciva-Pharmaceuticals, Prague, Czechoslovakia
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25
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Bidart JM, Troalen F, Salesse R, Bousfield GR, Bohuon CJ, Bellet DH. Topographic antigenic determinants recognized by monoclonal antibodies on human choriogonadotropin beta-subunit. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)47449-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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Lightbody JJ, Ziaja EL, Lugo SD, Mainwaring MG, Vinogradov SN, Shishikura F, Walz DA, Suzuki T, Gotoh T. Preparation and characterization of monoclonal antibodies to the extracellular hemoglobin of Lumbricus terrestris. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 873:340-9. [PMID: 3756184 DOI: 10.1016/0167-4838(86)90082-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Murine monoclonal antibodies to the extracellular hemoglobin of Lumbricus terrestris were prepared by a modification of the method of Kohler and Milstein. 224 hybridomas were found to produce antibodies which bound to the hemoglobin; they were tested for binding to the four subunits of the hemoglobin: M (chain I, 16 kDa), D1 (chain V, 31 kDa), D2 (chain VI, 37 kDa) and T (50 kDa), a disulfide-bonded trimer of chains II, III and IV, each of about 17 kDa. 150 hybridomas bound to all four subunits and 40 hybridomas bound to various combinations of subunits. The remaining 34 hybridomas combined only with the hemoglobin. The twelve hybridomas obtained after subculturing and cloning were tested for their binding to the two fractions II and III, consisting of subunits D1 + D2 + T and M, respectively, obtained by dissociation at pH 9.5 and at pH 4.0 and to the reassociated whole molecules, obtained subsequent to return to neutral pH. Eight hybridomas which combined only with the hemoglobin also combined with all the reassociated molecules but not with any of the fractions: these monoclonal antibodies probably recognize conformation-dependent antigenic sites that are present only in the hexagonal bilayer structure characteristic of the native and reassociated hemoglobin molecules. Of the remaining four hybridomas, two bound to subunit T and two combined with subunits T and D2; they also combined with the reassociated molecules and with the fractions II. In addition, the hybridomas did not bind to the hemoglobins of Tubifex, Limnodrilus, Arenicola, Tylorrhynchus and Macrobdella or to the chlorocruorins of Myxicola and Eudistylia.
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27
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Slaninová J, Brzeska H, Thorn NA. Characterization of a calmodulin antiserum by its reactions with fragments of the calmodulin molecule. JOURNAL OF IMMUNOASSAY 1986; 7:199-207. [PMID: 2427545 DOI: 10.1080/01971528608060466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A high affinity antibody, specific to the calcium-free form of calmodulin, which had previously been developed using N-acetyl-muramyl-L-alanyl-D-isoglutamine-calmodulin conjugate as an immunogen, was tested for cross-reactivity with tryptic fragments of calmodulin (CaM1-77, CaM1-90, CaM78-149, and CaM106-149) as well as with synthetic peptides corresponding to the 1st, 2nd, and 3rd calcium binding loop of calmodulin. The results showed that the antigenic determinant involves a special conformation of amino acid residues 90-106 in the 3rd calcium-binding domain.
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28
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Amit AG, Mariuzza RA, Phillips SE, Poljak RJ. Three-dimensional structure of an antigen-antibody complex at 2.8 A resolution. Science 1986; 233:747-53. [PMID: 2426778 DOI: 10.1126/science.2426778] [Citation(s) in RCA: 880] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The 2.8 A resolution three-dimensional structure of a complex between an antigen (lysozyme) and the Fab fragment from a monoclonal antibody against lysozyme has been determined and refined by x-ray crystallographic techniques. No conformational changes can be observed in the tertiary structure of lysozyme compared with that determined in native crystalline forms. The quaternary structure of Fab is that of an extended conformation. The antibody combining site is a rather flat surface with protuberances and depressions formed by its amino acid side chains. The antigen-antibody interface is tightly packed, with 16 lysozyme and 17 antibody residues making close contacts. The antigen contacting residues belong to two stretches of the lysozyme polypeptide chain: residues 18 to 27 and 116 to 129. All the complementarity-determining regions and two residues outside hypervariable positions of the antibody make contact with the antigen. Most of these contacts (10 residues out of 17) are made by the heavy chain, and in particular by its third complementarity-determining region. Antigen variability and antibody specificity and affinity are discussed on the basis of the determined structure.
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29
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Fanning DW, Smith JA, Rose GD. Molecular cartography of globular proteins with application to antigenic sites. Biopolymers 1986; 25:863-83. [PMID: 2424521 DOI: 10.1002/bip.360250509] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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30
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Bahraoui E, el Ayeb M, Van Rietschoten J, Rochat H, Granier C. Immunochemistry of scorpion alpha-toxins: study with synthetic peptides of the antigenicity of four regions of toxin II of Androctonus australis Hector. Mol Immunol 1986; 23:357-66. [PMID: 3724756 DOI: 10.1016/0161-5890(86)90133-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sequences 19-29 and 28-39 of toxin II of the North African scorpion Androctonus australis Hector have been synthesized. These two peptides correspond to the highest peaks in the hydrophilicity profile of toxin II and were thus believed to account for a significant proportion of toxin antigenicity. Affinity chromatography of solid-phase-bonded peptides allowed us to purify two sub-populations from the total IgGs raised against the native toxin. They both still bound to 125I-toxin II and showed a restricted heterogeneity in their specificity. Solid-phase immunoassays confirmed the antigenicity of these synthetic peptides and also that of two other previously described synthetic replicates of the antigenic regions of toxin II: sequences (5-14) S-S (60-64) and 50-59. The location of the four antigenic regions relative to the postulated location of the receptor-binding site of the toxin is discussed.
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31
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Dorow DS, Shi PT, Carbone FR, Minasian E, Todd PE, Leach SJ. Two large immunogenic and antigenic myoglobin peptides and the effects of cyclisation. Mol Immunol 1985; 22:1255-64. [PMID: 4079944 DOI: 10.1016/0161-5890(85)90044-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Peptides corresponding to sequences (72-88) and (26-54) of beef myoglobin have been synthesised in their open-chain and cyclised forms (using a disulphide bridge) and tested for their antigenicity and immunogenicity. Antibodies raised to beef myoglobin bound to both peptides but more strongly to the 29-residue than to the 17-residue peptide. Cyclisation increased the antigenicity of the larger peptide. In this form the peptide competed much more strongly than in the uncyclised form for specific antibodies to beef myoglobin. The peptides are immunogenic in mice without being coupled to a protein carrier and produce antibodies which bind to beef myoglobin. Peptide (26-54) is the more immunogenic in producing a larger antibody titre to the parent myoglobin and cyclisation again enhances this property. The findings lend weight to the view that longer peptide sequences might be expected to favour the folded state, therefore binding more strongly to antibodies raised to the native protein and eliciting a population of antibodies which contain a larger proportion specific for that conformation. Cyclisation enhances antigenicity and immunogenicity presumably by decreasing the number of degrees of conformational freedom of a peptide without excluding native-like conformations.
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32
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Abstract
Recent advances in the preparation of synthetic peptide vaccines and the use of synthetic peptides as probes of antigenic structure and function have led to renewed interest in the prediction of antigenic sites recognized by antibodies and T cells. This review focuses on antibodies. Features intrinsic to the antigen, such as hydrophilicity and mobility, may be useful in the selection of amino acid sequences of the native protein that will elicit antibodies cross-reacting with peptides, or sequences which, as peptides, will be more likely to elicit antibodies cross-reactive with the native protein. Structural mobility may also contribute to protein-protein interactions in general. However, the entire accessible surface of a protein is likely to be detectable by a large enough panel of antibodies. Which of these antibodies are made in any individual depends on factors extrinsic to the antigen molecule, host factors such as self-tolerance, immune response genes, idiotype networks, and the immunoglobulin structural gene repertoire.
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33
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Underwood PA, Bean PA. The influence of methods of production, purification and storage of monoclonal antibodies upon their observed specificities. J Immunol Methods 1985; 80:189-97. [PMID: 4008939 DOI: 10.1016/0022-1759(85)90020-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A panel of 38 monoclonal antibodies was exposed to a variety of physical conditions commonly used in their purification and storage. Reactivity with the homologous (immunising) antigen was reduced in a significant proportion (42%) of antibodies following these physical treatments. Sensitivity to particular physical treatments correlated with antibody subclass. In 3 cases the relative specificity of the antibody (as measured by cross-reactivity with 16 closely related antigens) was also altered. Following passage of the cloned hybridomas as ascites, 3 antibodies exhibited marked differences in specificity, which suggested the selection of different genotypes. The importance of documenting the methods of production, purification and storage of particular monoclonal antibodies used in comparative assay is stressed.
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34
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Briand JP, Muller S, Van Regenmortel MH. Synthetic peptides as antigens: pitfalls of conjugation methods. J Immunol Methods 1985; 78:59-69. [PMID: 2580027 DOI: 10.1016/0022-1759(85)90329-1] [Citation(s) in RCA: 240] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Peptide-carrier conjugates were prepared using 9 different synthetic peptides, 3 carrier proteins and 4 coupling reagents. Residues of the carrier protein that were modified by different coupling reagents (e.g., glutaraldehyde, carbodiimides, bis-diazotized benzidine) were found to elicit specific antibodies that reacted with unrelated carrier proteins treated with the same coupling agent. To demonstrate the presence of peptide antibodies in an antiserum raised against a peptide-carrier conjugate, it was necessary to use a antigen the peptide coupled to another carrier by means of a different coupling agent. Some of the commonly used conjugation methods were found to lead to conjugates of insufficient stability and sometimes also altered the antigenic properties of the peptide moiety. These difficulties can be overcome by additional control experiments designed to test the quality and the peptide-carrier conjugates.
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35
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Muller S, Couppez M, Briand JP, Gordon J, Sautière P, van Regenmortel MH. Antigenic structure of histone H2B. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 827:235-46. [PMID: 2578822 DOI: 10.1016/0167-4838(85)90208-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Antigenic determinants of histone H2B were localized using a series of 23 overlapping fragments of H2B obtained either by chemical and enzymatic cleavage of the histone or by solid-phase peptide synthesis. The ability of peptides to bind H2B antibodies was measured in an enzyme-linked immunosorbent assay, using antisera directed against calf thymus and chicken erythrocyte H2B as well as four anti H2B monoclonal antibodies obtained from autoimmune mice. Seven antigenic determinants were localized in the H2B molecule in the vicinity of residues 1-11, 6-18, 15-25, 26-35, 50-65, 94-113 and 114-125. Two of these determinants (residues 6-18 and 26-35) were revealed only through the binding properties of antibodies isolated from autoimmune mice. The usual correlation between hydrophilicity and antigenicity was found to hold for four of the epitopes, and the N- and C-termini of H2B were both antigenically active.
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36
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Altschuh D, Al Moudallal Z, Briand JP, Van Regenmortel MH. Immunochemical studies of tobacco mosaic virus--VI. Attempts to localize viral epitopes with monoclonal antibodies. Mol Immunol 1985; 22:329-37. [PMID: 2582247 DOI: 10.1016/0161-5890(85)90169-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The specificity of 18 monoclonal antibodies directed to tobacco mosaic virus (TMV) was studied by measuring their ability to bind to viral mutants, to other tobamoviruses, to dissociated viral subunits and to peptide fragments of the viral coat protein. The apparent binding specificity of the antibodies was dependent on the type of enzyme-linked immunosorbent assay used, probably because the antigens were disrupted or denatured when attached to the plastic surface of microtiter wells. The capacity of different monoclonal antibodies to detect single substitutions in the viral coat protein was used to delineate some of the topographic epitopes of TMV. By means of computer-generated images of the surface residues of the viral subunit, it was possible to identify certain clusters of residues involved in binding to some of the monoclonal antibodies. The results clearly illustrate the operational limitations encountered when monoclonal antibodies are used for elucidating the antigenic structure of proteins.
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37
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Paterson Y. Delineation and conformational analysis of two synthetic peptide models of antigenic sites on rodent cytochrome c. Biochemistry 1985; 24:1048-55. [PMID: 2581606 DOI: 10.1021/bi00325a037] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Two regions of rodent cytochrome c, one within the first four residues of the molecule, which is N-acetylated, and one at a beta bend around residue 44, are known to be immunogenic and antigenic in rabbits. Using sequential peptide synthesis, we have determined the residues required for linear synthetic peptides within these sequences to bind to antibody raised in rabbits to intact rat cytochrome c. The residues that were important in binding the N-terminal peptides were N-acetylglycine at position 1 and valine at position 3. The smallest peptide sequence around residue 44 that would bind to antibodies was Gln-Ala-Ala-Gly-Phe. A theoretical conformational analysis of these peptides showed that the amino-terminal tetrapeptide adopts a wide statistical ensemble of conformational states and that the addition of residues beyond 41 and 45 in the other sequence does not appear to stabilize longer peptides in the native beta-bend conformation. Thus, the antigenicity conferred by Phe-46 and Gln-42 in this peptide is most likely due to the direct interaction of the side chains of these residues with the antibody binding site. The demonstration here that native conformation is not essential for antigenic peptides to bind to antibodies raised against the whole protein indicates that the association energy between antigen and antibody can be sufficient to induce conformation in conformationally flexible peptides. This supports the concept that anti-protein and anti-peptide antibodies may invoke conformational changes in cross-reactive protein antigens and may explain why longer peptides, which may adopt stable nonnative secondary structure, often do not bind to antibodies raised to the whole molecule.
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38
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Eisenberg RJ, Long D, Ponce de Leon M, Matthews JT, Spear PG, Gibson MG, Lasky LA, Berman P, Golub E, Cohen GH. Localization of epitopes of herpes simplex virus type 1 glycoprotein D. J Virol 1985; 53:634-44. [PMID: 2578577 PMCID: PMC254679 DOI: 10.1128/jvi.53.2.634-644.1985] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We previously defined eight groups of monoclonal antibodies which react with distinct epitopes of herpes simplex virus glycoprotein D (gD). One of these, group VII antibody, was shown to react with a type-common continuous epitope within residues 11 to 19 of the mature glycoprotein (residues 36 to 44 of the predicted sequence of gD). In the current investigation, we have localized the sites of binding of two additional antibody groups which recognize continuous epitopes of gD. The use of truncated forms of gD as well as computer predictions of secondary structure and hydrophilicity were instrumental in locating these epitopes and choosing synthetic peptides to mimic their reactivity. Group II antibodies, which are type common, react with an epitope within residues 268 to 287 of the mature glycoprotein (residues 293 to 312 of the predicted sequence). Group V antibodies, which are gD-1 specific, react with an epitope within residues 340 to 356 of the mature protein (residues 365 to 381 of the predicted sequence). Four additional groups of monoclonal antibodies appear to react with discontinuous epitopes of gD-1, since the reactivity of these antibodies was lost when the glycoprotein was denatured by reduction and alkylation. Truncated forms of gD were used to localize these four epitopes to the first 260 amino acids of the mature protein. Competition experiments were used to assess the relative positions of binding of various pairs of monoclonal antibodies. In several cases, when one antibody was bound, there was no interference with the binding of an antibody from another group, indicating that the epitopes were distinct. However, in other cases, there was competition, indicating that these epitopes might share some common amino acids.
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39
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40
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Atassi MZ. Perspectives of the immunology of proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1985; 185:1-25. [PMID: 2416195 DOI: 10.1007/978-1-4684-7974-4_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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41
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Atassi MZ. Antigenic structures of proteins. Their determination has revealed important aspects of immune recognition and generated strategies for synthetic mimicking of protein binding sites. EUROPEAN JOURNAL OF BIOCHEMISTRY 1984; 145:1-20. [PMID: 6208027 DOI: 10.1111/j.1432-1033.1984.tb08516.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Studies in this laboratory have resulted in the delineation and synthetic verification of several complete protein antigenic structures that are recognized by antibodies. More recently, for the first time, the full profiles of the sites that are recognized by T cells have been localized and confirmed by synthesis for two proteins, myoglobin and lysozyme. These have thus far constituted the only complete antigenic structures to be determined. The availability of these antigenic structures has enabled us to investigate in detail the molecular and cellular parameters responsible for immune recognition, responses to, and control and regulation of these responses to protein antigens at the molecular and submolecular levels. Moreover, these investigations have afforded general strategies for the synthetic mimicking of not only antigenic sites, but also protein binding sites involved in other biological activities.
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42
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Westhof E, Altschuh D, Moras D, Bloomer AC, Mondragon A, Klug A, Van Regenmortel MH. Correlation between segmental mobility and the location of antigenic determinants in proteins. Nature 1984; 311:123-6. [PMID: 6206398 DOI: 10.1038/311123a0] [Citation(s) in RCA: 504] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Most continuous antigenic determinants of tobacco mosaic virus protein (TMVP), myoglobin and lysozyme correspond to those surface regions in the protein structure, as determined by X-ray crystallography, which possess a run of high-temperature factors along the polypeptide backbone, that is, a high segmental mobility. The mobility of an antigenic determinant may make it easier to adjust to a pre-existing antibody site not fashioned to fit the exact geometry of a protein. The correlation found between temperature factors and antigenicity is better than that between hydrophilicity and antigenicity.
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43
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Underwood PA. An antigenic map of the haemagglutinin of the influenza Hong Kong subtype (H3N2), constructed using mouse monoclonal antibodies. Mol Immunol 1984; 21:663-71. [PMID: 6205255 DOI: 10.1016/0161-5890(84)90052-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Panels of monoclonal antibodies were raised to the haemagglutinin of strains of the Hong Kong subtype of influenza (H3N2), namely Hong Kong 1968, England 1972, Port Chalmers 1973, Victoria 1975 and Texas 1977. The probable binding sites of individual antibodies in each panel were determined by correlation of cross-reactivity with 16 heterologous strains from the same subtype, and amino acid differences between their haemagglutinin molecules. This led to an approximation of the "average repertoire" of the BALB/c mouse to influenza type A haemagglutinin. Comparative data of the cross-reactivity of whole mouse sera suggested that the monoclonal panels derived from spleen cells were a fair representation of circulating antibody. Variation in the cross-reactivities of individual sera approached that of individual monoclonal antibodies. The relevance of this finding to selection of new virus variants in the human population was discussed. Heterospecific antibodies were detected in some monoclonal panels. Specific amino acid changes which could be responsible for such activity were identified.
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44
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Shi PT, Riehm JP, Todd PE, Leach SJ. The antigenicity of myoglobin-related peptides synthesised on polyacrylamide and polystyrene resin supports. Mol Immunol 1984; 21:489-96. [PMID: 6749134 DOI: 10.1016/0161-5890(84)90064-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Polyacrylamide resins [Atherton et al., Bioorg. Chem. 8, 351-370 (1979)] have been found suitable for solid-phase radioimmunoassay of peptides synthesised on the same supports; they are sufficiently stable during side-chain deprotection and swell sufficiently in aq. media to admit antibody molecules to the sites of peptide attachment. A re-examination of five synthetic peptide sequences corresponding to (15-21), (56-62), (94-99), (113-119) and (145-151) of beef myoglobin analogous to those delineated by Atassi [Immunochemistry 12, 423-438 (1975)] for sperm whale myoglobin shows that they all bind anti-beef myoglobin antibodies raised in rabbits, with binding capacities in the order V = III greater than IV greater than I = II. The resin-bound peptide (72-88) binds such antibodies even more extensively, as do certain sequential variants of peptide V. Other peptides, bound to polyacrylamide or polystyrene resins but unrelated to any of the five sequences and varying in size and amino acid composition and sequence were also tested with various antisera. It was concluded that the antibody binding properties of the 30 or so small peptides (two-seven residues) are dominated by their cationic and/or hydrophobic properties. In small peptides, therefore, antibody binding can be safely interpreted only in terms of general structural properties but not in terms of biological specificity. The latter property becomes assessable only with peptides representing larger areas of antigenic protein surfaces.
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45
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El Ayeb M, Bahraoui EM, Granier C, Delori P, Van Rietschoten J, Rochat H. Immunochemistry of scorpion alpha-toxins: purification and characterization of two functionally independent IgG populations raised against toxin II of Androctonus australis Hector. Mol Immunol 1984; 21:223-32. [PMID: 6201732 DOI: 10.1016/0161-5890(84)90077-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We report the isolation and characterization of two IgG populations specific to two synthetic peptides corresponding to two antigenic sites of toxin II of the North African scorpion Androctonus australis Hector. Firstly, thanks to the use of: (1) antigenic homology studies between toxin II of A. australis Hector and toxin III of Buthus occitanus tunetanus, (2) chemical modification of toxin II of A. australis Hector, and (3) prediction of the localization of the four major antigenic sites of scorpion alpha-toxins by the method developed by Hopp and Woods [Proc. natn. Acad. Sci. U.S.A. 78, 3824-3828 (1981)], we have established that the region around the disulfide bridge between cysteines 12 and 63 as well as the stretch of residues 50-59 probably each enclosed an antigenic site. Secondly, the synthetic replicates of these regions linked to Sepharose allowed us to isolate, by immunoaffinity chromatography, two IgG populations from the whole anti-toxin II of A. australis Hector IgGs. Finally, each of these two IgG populations was shown to be specific to one antigenic site as evidenced by the multideterminant effect on the slopes of binding curves developed by Berzofsky et al. [Biochemistry 15, 2113-2121 (1976)]. Furthermore, these two IgG populations were found to be functionally independent and this could be related to the fact that the two regions carrying the two antigenic sites are not close to each other in space and that there is neither steric hindrance nor cooperative effects between them. The association constant of these site-specific IgG populations was calculated and found to be equal to 1.18-5.14 X 10(9) l/mole for IgG anti-site 1 and 1.16-5.62 X 10(9) l/mole for IgG anti-site 2 respectively by Sips [J. chem. Phys. 16, 490-495 (1948)], Scatchard [Am. N.Y. Acad. Sci. 51, 660-772 (1949)] and Steward and Petty [Immunology 23, 881-887 (1972)] representations. The index of heterogeneity of 0.9 for anti-P1 and anti-P2 indicates the purification of essentially homogeneous affinity IgG populations.
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Granier C, Bahraoui E, Van Rietschoten J, Rochat H, El Ayeb M. Synthesis and immunological characterization of two peptides which are models for two of the four major antigenic sites of a scorpion toxin. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1984; 23:187-97. [PMID: 6199319 DOI: 10.1111/j.1399-3011.1984.tb02709.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We have synthesized, by the solid phase procedure, then purified and chemically characterized two peptides. They mimic two regions of toxin II of the scorpion Androctonus australis Hector, one around disulfide bridge 12-63 and another at sequence 50-59. Each of these two regions was supposed to include an antigenic site. We have shown that the synthetic replicas of these regions are individually recognized by a part of IgGs raised against native toxin II. This is a strong argument for the involvement of these areas in the antigenicity of the toxin. Furthermore, region-specific IgGs purified by affinity chromatography on the two Sepharose linked peptides were able to bind 125I-labelled toxin II.
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