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Krebs SK, Stech M, Jorde F, Rakotoarinoro N, Ramm F, Marinoff S, Bahrke S, Danielczyk A, Wüstenhagen DA, Kubick S. Synthesis of an Anti-CD7 Recombinant Immunotoxin Based on PE24 in CHO and E. coli Cell-Free Systems. Int J Mol Sci 2022; 23:ijms232213697. [PMID: 36430170 PMCID: PMC9697001 DOI: 10.3390/ijms232213697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/04/2022] [Accepted: 11/05/2022] [Indexed: 11/09/2022] Open
Abstract
Recombinant immunotoxins (RITs) are an effective class of agents for targeted therapy in cancer treatment. In this article, we demonstrate the straight-forward production and testing of an anti-CD7 RIT based on PE24 in a prokaryotic and a eukaryotic cell-free system. The prokaryotic cell-free system was derived from Escherichia coli BL21 StarTM (DE3) cells transformed with a plasmid encoding the chaperones groEL/groES. The eukaryotic cell-free system was prepared from Chinese hamster ovary (CHO) cells that leave intact endoplasmic reticulum-derived microsomes in the cell-free reaction mix from which the RIT was extracted. The investigated RIT was built by fusing an anti-CD7 single-chain variable fragment (scFv) with the toxin domain PE24, a shortened variant of Pseudomonas Exotoxin A. The RIT was produced in both cell-free systems and tested for antigen binding against CD7 and cell killing on CD7-positive Jurkat, HSB-2, and ALL-SIL cells. CD7-positive cells were effectively killed by the anti-CD7 scFv-PE24 RIT with an IC50 value of 15 pM to 40 pM for CHO and 42 pM to 156 pM for E. coli cell-free-produced RIT. CD7-negative Raji cells were unaffected by the RIT. Toxin and antibody domain alone did not show cytotoxic effects on either CD7-positive or CD7-negative cells. To our knowledge, this report describes the production of an active RIT in E. coli and CHO cell-free systems for the first time. We provide the proof-of-concept that cell-free protein synthesis allows for on-demand testing of antibody−toxin conjugate activity in a time-efficient workflow without cell lysis or purification required.
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Affiliation(s)
- Simon K. Krebs
- Branch Bioanalytics and Bioprocesses (IZI-BB), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Am Mühlenberg 13, 14476 Potsdam, Germany
- Institute for Biotechnology, Technical University of Berlin, Ackerstrasse 76, 13355 Berlin, Germany
| | - Marlitt Stech
- Branch Bioanalytics and Bioprocesses (IZI-BB), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Am Mühlenberg 13, 14476 Potsdam, Germany
| | - Felix Jorde
- Branch Bioanalytics and Bioprocesses (IZI-BB), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Am Mühlenberg 13, 14476 Potsdam, Germany
| | - Nathanaël Rakotoarinoro
- Branch Bioanalytics and Bioprocesses (IZI-BB), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Am Mühlenberg 13, 14476 Potsdam, Germany
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Strasse 2 + 4, 14195 Berlin, Germany
| | - Franziska Ramm
- Branch Bioanalytics and Bioprocesses (IZI-BB), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Am Mühlenberg 13, 14476 Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Sophie Marinoff
- Glycotope GmbH, Robert-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Sven Bahrke
- Glycotope GmbH, Robert-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Antje Danielczyk
- Glycotope GmbH, Robert-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Doreen A. Wüstenhagen
- Branch Bioanalytics and Bioprocesses (IZI-BB), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Am Mühlenberg 13, 14476 Potsdam, Germany
| | - Stefan Kubick
- Branch Bioanalytics and Bioprocesses (IZI-BB), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Am Mühlenberg 13, 14476 Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
- Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus-Senftenberg, The Brandenburg Medical School Theodor Fontane and the University of Potsdam, 14476 Potsdam, Germany
- Correspondence:
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Abstract
Immunotoxins constitute a new modality for the treatment of cancer, since they target cells displaying specific surface-receptors or antigens. Immunotoxins contain a ligand such as a growth factor, monoclonal antibody, or fragment of an antibody which is connected to a protein toxin. After the ligand subunit binds to the surface of the target cell, the molecule internalizes and the toxin kills the cell. Bacterial toxins which have been targeted to cancer cells include Pseudomonas exotoxin and diphtheria toxin, which are well suited to forming recombinant single-chain or double-chain fusion toxins. Plant toxins include ricin, abrin, pokeweed antiviral protein, saporin and gelonin, and have generally been connected to ligands by disulfide-bond chemistry. Immunotoxins have been produced to target hematologic malignancies and solid tumors via a wide variety of growth factor receptors and antigens. Challenges facing the clinical application of immunotoxins are discussed.
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Affiliation(s)
- I Pastan
- Laboratory of Molecular Biology, Division of Cancer Biology, National Cancer Institute, National Institutes of Health, 37/4E16, 37 Convent Drive MSC 4255, Bethesda, MD 20892, USA
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Affiliation(s)
- J R Kalden
- Department of Internal Medicine III, University Hospital Erlangen-Nürnberg, Germany
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Olsen NJ, Brooks RH, Cush JJ, Lipsky PE, St Clair EW, Matteson EL, Gold KN, Cannon GW, Jackson CG, McCune WJ, Fox DA, Nelson B, Lorenz T, Strand V. A double-blind, placebo-controlled study of anti-CD5 immunoconjugate in patients with rheumatoid arthritis. The Xoma RA Investigator Group. Arthritis Rheum 1996; 39:1102-8. [PMID: 8670317 DOI: 10.1002/art.1780390705] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To evaluate the efficacy of an anti-CD5 ricin-linked immunoconjugate (CD5-IC) in patients with rheumatoid arthritis (RA). METHODS A total of 104 evaluable patients were enrolled in a multicenter, double-blind, multiple-dose, placebo-controlled study of CD5-IC. RESULTS Treatment with CD5-IC in doses up to 8 mg/m2/day for 4 days in 1 month failed to produce marked or prolonged T cell depletion and was no more effective than placebo in ameliorating disease manifestations. An unexpectedly high placebo response was observed in 48% of the patients. Adverse events were correlated with the dose of CD5-IC, but the treatment was generally well-tolerated. CONCLUSION At the doses used in this study, CD5-IC was ineffective for treating RA.
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Affiliation(s)
- N J Olsen
- Vanderbilt University, Nashville, Tennessee 37232, USA
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Better M, Bernhard SL, Williams RE, Leigh SD, Bauer RJ, Kung AH, Carroll SF, Fishwild DM. T cell-targeted immunofusion proteins from Escherichia coli. J Biol Chem 1995; 270:14951-7. [PMID: 7541032 DOI: 10.1074/jbc.270.25.14951] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Fusion proteins between cell-targeting domains and cytotoxic proteins should be particularly effective therapeutic reagents. We constructed a family of immunofusion proteins linking humanized Fab, F(ab')2, or single chain antibody forms of the H65 antibody (which recognizes the CD5 antigen on the surface of human T cells) with the plant ribosome-inactivating protein gelonin. We reasoned that such an immunofusion would kill human target cells as efficiently as the previously described chemical conjugates of H65 and gelonin (Better M., Bernhard, S. L., Fishwild, D. M., Nolan, P. A., Bauer, R. J., Kung, A. H. C., and Carroll, S. F. (1994) J. Biol. Chem. 269, 9644-9650) if both the recognition and catalytic domains remained active, and a proper linkage between domains could be found. Immunofusion proteins were produced in Escherichia coli as secreted proteins and were recovered directly from the bacterial culture supernatant in an active form. All of the immunofusion proteins were purified by a common process and were tested for cytotoxicity toward antigen-positive human cells. A 20-60-fold range of cytotoxic activity was seen among the fusion family members, and several fusion proteins were identified which are approximately as active as effective chemical conjugates. Based on these constructs, immunofusion avidity and potency can be controlled by appropriate selection of antibody domains and ribosome-inactivating protein.
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Affiliation(s)
- M Better
- XOMA Corporation, Santa Monica, California 90404, USA
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Fishwild DM, Wu HM, Carroll SF, Bernhard SL. Characterization of the increased cytotoxicity of gelonin anti-T cell immunoconjugates compared with ricin A chain immunoconjugates. Clin Exp Immunol 1994; 97:10-8. [PMID: 8033405 PMCID: PMC1534791 DOI: 10.1111/j.1365-2249.1994.tb06572.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Ribosomal inactivating proteins such as gelonin (Gel) and ricin A chain (RTA) conjugated to MoAbs bind to specific target cells, and upon internalization inhibit protein synthesis, ultimately resulting in cell death. We report here that Gel anti-T cell MoAb conjugates are more cytotoxic than RTA conjugates when tested against human peripheral blood mononuclear cells (PBMC). This increased cytotoxicity is observed whether Gel is conjugated to the anti-T cell MoAb or to an anti-mouse immunoglobulin Fab' fragment which then binds to the murine anti-human T cell MoAb. Gel conjugates are not only effective at lower concentrations, but also produce a greater extent of inhibition of cellular proliferation. Moreover, a 10 min exposure to a Gel conjugate is as effective as a 90 h exposure to an RTA conjugate. When part of anti-T cell F(ab')2 or Fab' conjugates, Gel affects the early steps in cellular intoxication more than RTA; Gel conjugates bind more avidly and accelerate the modulation of antigen. In contrast, when part of whole IgG conjugates, Gel does not affect the binding to or modulation of surface antigen compared with RTA, while it does increase conjugate cytotoxicity. These observations suggest that Gel may be delivered more efficiently into the cytosol than RTA. A divergent intracellular pathway for Gel is also supported by the inability of chemical potentiators, which strongly enhance RTA potency, to affect Gel potency. These properties of Gel might also be advantageous for immunoconjugates made with other MoAbs or receptor-binding molecules.
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Affiliation(s)
- D M Fishwild
- Department of Immunology, XOMA Corporation, Berkeley, CA
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Better M, Bernhard S, Fishwild D, Nolan P, Bauer R, Kung A, Carroll S. Gelonin analogs with engineered cysteine residues form antibody immunoconjugates with unique properties. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36930-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Kohn FR, Fishwild DM, Bernhard SL, Better M, Kung AH. Efficacy of anti-CD5 F(ab')2 and Fab' immunoconjugates in human peripheral blood lymphocyte-reconstituted severe combined immunodeficient mice. Int J Immunopharmacol 1993; 15:871-8. [PMID: 7504661 DOI: 10.1016/0192-0561(93)90004-i] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A human peripheral blood lymphocyte-reconstituted severe combined immunodeficient (hu-PBL-SCID) mouse model was used to compare in vivo efficacy of immunoconjugates directed against the CD5 antigen present on human T-cells. Four anti-CD5 immunoconjugates were tested, composed of chimeric human-mouse (cH65) F(ab')2 or Fab' fragments chemically linked to recombinant gelonin (rGEL) or the 30,000 M(r) glycoform of ricin A chain (RTA30). Immunoconjugate treatment was initiated approximately 3 weeks after PBL transplantation and consisted of five consecutive daily bolus i.v. injections. Efficacy was subsequently assessed by quantitation of human T-cells in spleens, blood and peritoneal lavage fluid using 3-color flow cytometry. cH65 F(ab')2- and cH65 Fab'-rGEL conjugates were essentially equally effective at depleting human T-cells from SCID mouse tissues, suggesting that bivalent binding is not required for efficacy when rGEL is the cytotoxic moiety. Treatment with unconjugated F(ab')2, unconjugated Fab' or a Fab-rGEL immunoconjugate of irrelevant binding specificity did not result in a significant depletion of T-cells, demonstrating that the cytotoxic moiety and a relevant human T-cell binding moiety are both required for efficacy. In contrast to the results observed with the rGEL conjugates, cH65 Fab'-RTA30 was not as effective as cH65 F(ab')2-RTA30 in depleting human T-cells from SCID mouse tissues. This paralleled in vitro findings in a human PBMC cytotoxicity assay, which demonstrated that cH65 Fab'-RTA30 was 17-fold less potent than cH65 F(ab')2-RTA30 and approximately 50-fold less potent than the rGEL conjugates.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- F R Kohn
- Department of Pharmacology and Toxicology, XOMA Corporation, Berkeley, CA 94710
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Kohn FR, Fishwild DM, Kung AH. Efficacy of an anti-CD5-ricin A chain immunoconjugate in an improved human peripheral blood lymphocyte--reconstituted severe combined immunodeficient mouse model. Int J Immunopharmacol 1993; 15:695-709. [PMID: 7691766 DOI: 10.1016/0192-0561(93)90142-l] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Severe combined immunodeficient mice reconstituted with human peripheral blood lymphocytes (hu-PBL-SCID mice) were used to evaluate in vivo efficacy of a mouse IgG1 monoclonal antibody (mAb)-ricin toxin A chain immunoconjugate (H65-RTA) directed against the CD5 cell surface antigen present on human T-cells. Initial studies demonstrated that plasma levels of human soluble interleukin-2 receptor (sIL-2R) are predictive of human T-cell engraftment in spleens and blood of SCID mice transplanted with human PBL. Therefore, chimeric mice with detectable plasma levels of human sIL-2R were used in subsequent studies. Systemic injection of such mice with H65-RTA resulted in a significant depletion of human T-cells from spleens, blood and bone marrow, and a decrease in plasma levels of human sIL-2R as compared to vehicle-treated control animals. The effect of H65-RTA was dose-dependent, treatment schedule-dependent, and mAb-specific, as an isotype-, linker- and toxin-matched immunoconjugate of irrelevant binding specificity was not efficacious. Moreover, human T-cells remained depleted from SCID tissues for at least 10 days after cessation of H65-RTA treatment, indicating that the cells were killed by the immunoconjugate. Unconjugated H65 mAb and an H65-derived F(ab')2-RTA conjugate, but not unconjugated F(ab')2, were also efficacious, suggesting that the Fc portion of the mAb and the toxin moiety may both play a role in the mechanism of human T-cell depletion by H65-RTA in this model. Results indicate that the hu-PBL-SCID mouse model can be used to compare in vivo efficacy of immunosuppressive agents specifically directed against human T-cells.
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Affiliation(s)
- F R Kohn
- Department of Pharmacology and Toxicology, XOMA Corporation, Berkeley, CA 94710
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Strand V, Lipsky PE, Cannon GW, Calabrese LH, Wiesenhutter C, Cohen SB, Olsen NJ, Lee ML, Lorenz TJ, Nelson B. Effects of administration of an anti-CD5 plus immunoconjugate in rheumatoid arthritis. Results of two phase II studies. The CD5 Plus Rheumatoid Arthritis Investigators Group. Arthritis Rheum 1993; 36:620-30. [PMID: 7683881 DOI: 10.1002/art.1780360508] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To evaluate the safety and activity of an immunoconjugate of ricin A chain and anti-CD5 monoclonal antibody (anti-CD5 IC), with and without concomitant methotrexate and/or azathioprine, in the treatment of rheumatoid arthritis (RA). METHODS Seventy-nine patients with active RA were enrolled in 2 prospective open-label protocols. RESULTS Using composite criteria, response rates were 50-68% at 1 month and 22-25% at 6 months. Transient depletion of CD3/CD5 T cells was observed on days 2 and 5 of treatment, with reconstitution on day 15 or day 29. Treatment-associated adverse effects were common but resolved rapidly without sequelae. CONCLUSION These findings suggest activity of anti-CD5 IC in active RA and warrant confirmation in a multicenter randomized study (currently underway).
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Better M, Bernhard SL, Lei SP, Fishwild DM, Lane JA, Carroll SF, Horwitz AH. Potent anti-CD5 ricin A chain immunoconjugates from bacterially produced Fab' and F(ab')2. Proc Natl Acad Sci U S A 1993; 90:457-61. [PMID: 7678457 PMCID: PMC45682 DOI: 10.1073/pnas.90.2.457] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have used genetic engineering to obtain secretion of anti-human CD5 antibody fragments from Escherichia coli for conjugation to the 30-kDa form of ricin A chain (RTA30). This was accomplished by introducing stop codons at two positions in the hinge region of the human IgG1 gene so that coexpression of the truncated heavy-chain genes (Fd') with a light chain would result in Fab' and/or F(ab')2 proteins containing either one or two interheavy-chain cysteines. An Fd' gene encoding both interheavy-chain cysteines yielded a mixture of F(ab')2 and Fab', which could be separated by size-exclusion chromatography. An Fd' gene encoding only one interheavy-chain cysteine yielded primarily Fab'. Purified F(ab')2 protein was equivalent to unlabeled chimeric IgG in competing for binding of IgG with CD5 antigen, while the molar concentration of the monovalent Fab' required for 50% binding inhibition was 4- to 5-fold higher than IgG. An immunoconjugate was prepared with Fab' by direct coupling to the unique free cysteine on RTA30. The bivalent F(ab')2 was conjugated to RTA30 after derivatization with the crosslinking agent 5-methyl-2-iminothiolane. These immunoconjugates efficiently killed a CD5+ T-cell line and human peripheral blood T cells.
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Affiliation(s)
- M Better
- XOMA Corporation, Santa Monica, CA 90404
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