Role of the B-Chain in the Cytotoxic Action of Antibody-Ricin and Antibody-Abrin Conjugates

  • Deirdre McIntosh
  • Philip Thorpe


Attempts have been made in several laboratories to construct cell type-specific cytotoxic agents by linking antibody molecules to the highly potent toxins, abrin and ricin (for a review of the mode of action of abrin and ricin, see chapter by S. Olsnes, this volume). Two main strategies have been adopted. The first is to link the holotoxin directly to the antibody. Conjugates of this type always appear to exert a powerful cytotoxic effect upon cells with the appropriate antigens but suffer from a lack of complete specificity because they can also bind to non-target cells by the galactose-binding sites on the toxin B-chain (reviewed by Thorpe et al., 1982a). The other approach is to link the antibody by a disulfide bond to the isolated toxin A-chain. Conjugates of this second type, although free from the problem of non-specific binding, show great variability in cytotoxic potency, some being as effective as the native toxin and others being weakly or non-cytotoxic (reviewed by Olsnes and Pihl, 1982a; Martinez et al., 1982; Thorpe et al., 1982a). The consistent and generally superior cytotoxic performance of the intact toxin conjugates appears to be attributable to an ability of the B-chain to facilitate delivery of the A-chain moiety to the cytosol.


Diphtheria Toxin Sepharose Column Imperial Cancer Research Fund Antibody Moiety Specific Cytotoxic Effect 
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  1. Beugnier, N., Falmagne, P., Zanen, J. and Jansen, F.K., 1982, Interaction of ricin and its two chains with model membranes, Archives Internationales de Physiologie et Biochimie, 90:93.Google Scholar
  2. Cawley, D.B., Herschman, H.R., Gilliland, D.G. and Collier, R.J., 1980, Epidermal growth factor — toxin A chain conjugates: EGF-ricin A is a potent toxin while EGF-diphtheria fragment A is non-toxic, Cell, 22:563.PubMedCrossRefGoogle Scholar
  3. Cawley, D.B., Simpson, D.L. and Herschman, H.R., 1981, Asialoglyco-protein receptor mediates the toxic effects of an asiolo-fetuin-diphtheria toxin fragment A conjugate on cultured rat hepatocytes, Proc. Natl. Acad. Sci. U.S.A., 78:3383.PubMedCrossRefGoogle Scholar
  4. Casellas, P., Brown, J.P., Gros, O., Gros, P., Hellstrom, I., Jansen, F.K., Poncelet, P., Roncucci, R., Vidal, H. and Hellstrom, K.E., 1982, Human melanoma cells can be killed in-vitro by an immunotoxin specific for melanoma-associated antigen p97, Int. J. Cancer, 30:437.PubMedCrossRefGoogle Scholar
  5. Donovan, J., Simon, M. and Montai, M., 1982, Diphtheria toxin fragment A crosses lipid membranes at acid pH, Biophys. J., 37:256a.Google Scholar
  6. Draper, R.K. and Simon, M.I., 1980, The entry of diphtheria toxin into the mammalian cell cytoplasm: evidence for lysosomal involvement, J. Cell Biol., 87:849.PubMedCrossRefGoogle Scholar
  7. Fernandez-Puentes, C. and Carrasco, L., 1980, Viral infection per-meabilizes mammalian cells to protein toxins, Cell, 20:769.PubMedCrossRefGoogle Scholar
  8. Funatsu, G., Yoshitake, S. and Funatsu, M., 1978, Primary structure of Ile chain of ricin D, Agric. Biol. Chem., 42:501.CrossRefGoogle Scholar
  9. Houston, L.L., 1982, Transport of ricin A after prior treatment of mouse leukemia cells with ricin B chain, J. Biol. Chem., 257:1532.PubMedGoogle Scholar
  10. Houston, L.L., 1983, Inactivation of ricin using 4-azidophenyl-β-galactopyranoside and 4-diazophenyl-β-D-galactopyranoside, J. Biol. Chem., 258:7208.PubMedGoogle Scholar
  11. Ishida, B., Cawley, D.B., Reve, K. and Wisnieski, B.J., 1983, Lipid-protein interactions during ricin toxin insertion into membranes, J. Biol. Chem., 258:5933.PubMedGoogle Scholar
  12. Kimura, M. and Funatsu, G., 1981, Amino acid sequences of two cyanogen bromide fragments CB11 and CB111, and the complete sequence of Ala chain of ricin D, Agric. Biol. Chem., 45:277.CrossRefGoogle Scholar
  13. Lappi, D.A., Kapmeyer, W., Beglau, J.M. and Kaplan, N.O., 1978, The disulfide bond connecting the chains of ricin, Proc. Natl. Acad. Sci. U.S.A., 75:1096.PubMedCrossRefGoogle Scholar
  14. Martinez, O., Kimura, J., Gottfried, T.D., Zeicher, M. and Wofsy, L., 1982, Variance in cytotoxic effectiveness of antibody-toxin A hybrids, Cancer Surveys, 1:373.Google Scholar
  15. Mason, D.W., Thorpe, P.E. and Ross, W.C.J., 1982, Elimination of leukemic cells from rodent bone marrow in-vitro with antibody-ricin conjugates: implications for autologous marrow transplantation in man, Cancer Surveys, 1:389.Google Scholar
  16. Mcintosh, D.P., Edwards, D.C., Cumber, A.J., Parnell, G.D., Dean, C.J., Ross, W.C.J, and Forrester, J.A., 1983, Ricin B chain converts a non-cytotoxic antibody-ricin A chain conjugate into a potent and specific cytotoxic agent, FEBS Lett., 164:17.PubMedCrossRefGoogle Scholar
  17. Myers, C.D., Thorpe, P.E., Ross, W.C.J., Cumber, A.J., Katz, F.E. and Greaves, M.F., 1984, An immunotoxin with therapeutic potential in T cell leukemia — WTI-ricin A, Blood (in press).Google Scholar
  18. Olsnes, S. and Pihl, A., 1982a, Chimeric toxins, Pharmac. Ther., 15:355.CrossRefGoogle Scholar
  19. Olsnes, S. and Pihl, A., 1982b, Cytotoxic proteins with intracellular site of action: mechanism of action and anti-cancer properties, Cancer Surveys, 1:467.Google Scholar
  20. Sandvig, K., Olsnes, S. and Pihl, A., 1978, Chemical modifications of the toxic lectins abrin and ricin, Eur. J. Biochem., 84:323.PubMedCrossRefGoogle Scholar
  21. Sandvig, K. and Olsnes, S., 1980, Diphtheria toxin entry into cells is facilitated by low pH, J. Cell Biol., 87:828.PubMedCrossRefGoogle Scholar
  22. Sandvig, K. and Olsnes, S., 1981, Rapid entry of nicked diphtheria toxin into cells at low pH. Characterization of the entry process and effects of low pH on the toxin molecule, J. Biol. Chem., 256:9068.PubMedGoogle Scholar
  23. Sandvig, K. and Olsnes, S., 1982a, Entry of the toxic proteins abrin, modeccin, ricin and diphtheria toxin into cells. II. Effect of pH, metabolic inhibitors and ionophores and evidence for toxin penetration from endocytotic vesicles, J. Biol. Chem., 257:7504.PubMedGoogle Scholar
  24. Sandvig, K. and Olsnes, S., 1982b, Entry of the toxic proteins, abrin, modeccin, ricin and diphtheria toxin into cells. I. Requirement for calcium, J. Biol. Chem., 257:7495.PubMedGoogle Scholar
  25. Thorpe, P.E., Cumber, A.J., Williams, N., Edwards, D.C., Ross, W.C.J. and Davies, A.J.S., 1981, Abrogation of the non-specific toxicity of abrin conjugated to anti-lymphocyte globulin, Clin. Exp. Immunol., 43:195.PubMedGoogle Scholar
  26. Thorpe, P.E. and Ross, W.C.J., 1982, The preparation and cytotoxic properties of antibody-toxin conjugates, Immunol. Reviews, 62:119.CrossRefGoogle Scholar
  27. Thorpe, P.E., Edwards, D.C., Ross, W.C.J, and Davies, A.J.S., 1982a, Monoclonal antibody-toxin conjugates: aiming the magic bullet, in: “Monoclonal Antibodies in Clinical Medicine”, J. Fabre and A. McMichael, eds., Academic Press, London.Google Scholar
  28. Thorpe, P.E., Mason, D.W., Brown, A.N.F., Simmonds, S.J., Ross, W.C.J., Cumber, A.J. and Forrester, J.A., 1982b, Selective killing of malignant cells in a leukemic rat bone marrow with an antibody-ricin conjugate, Nature, 297:594.PubMedCrossRefGoogle Scholar
  29. Thorpe, P.E., Brown, A.N.F., Foxwell, B., Myers, C., Ross, W.C.J., Cumber, A.J. and Forrester, J.A., 1983a, Blockade of the galactose-binding site of ricin by its linkage to antibody, in: “Monoclonal Antibodies in Cancer”, B.D. Boss, R.E. Langman, I.S. Trowbridge and R. Dulbecco, eds., Academic Press, New York (in press).Google Scholar
  30. Thorpe, P.E., Ross, W.C.J., Brown, A.N.F., Myers, C., Cumber, A.J., Foxwell, B. and Forrester, J.A., 1983b, Blockade of the galactose binding sites of ricin by its linkage to antibody: specific cytotoxic effects of the conjugates, Eur. J. Biochem. (submitted for publication).Google Scholar
  31. Vitetta, E.S., Cushley, W. and Uhr, J.W., 1983, Synergy of ricin A chain — containing immunotoxins and ricin B chain — containing immunotoxins in the in-vitro killing of neoplastic human B cells, Proc. Natl. Acad. Sci. U.S.A., 80:6332.PubMedCrossRefGoogle Scholar
  32. White, R.A.H., Mason, D.W., Williams, A.F., Galfre, G. and Milstein, C., 1978 T-lymphocyte heterogeneity in the rat: separation of functional subpopulations using a monoclonal antibody, J. Exp. Med., 148:664.PubMedCrossRefGoogle Scholar
  33. Williams, A.F., Galfre, G. and Milstein, C., 1977, Analysis of cell surfaces by xenogeneic myeloma-hybrid antibodies: Differentiation antigens of rat lymphocytes, Cell, 12:663.PubMedCrossRefGoogle Scholar
  34. Youle, R.J. and Neville, D.M., 1980, Anti-Thy1.2 monoclonal antibody linked to ricin is a potent cell-type-specific toxin, Proc. Natl. Acad. Sci. U.S.A., 77:5483.PubMedCrossRefGoogle Scholar
  35. Youle, R.J., Murray, G.J. and Neville, D.M., Jr., 1981, Studies on the galactose-binding site of ricin and on the hybrid toxin Man-6-P-ricin, Cell, 23:551.PubMedCrossRefGoogle Scholar
  36. Youle, R.J. and Neville, D.M., 1982, Kinetics of protein synthesis inactivation by ricin-anti-Thy1.1 monoclonal antibody hybrids: role of the ricin B subunit demonstrated by reconstitution, J. Biol. Chem., 257:1598.PubMedGoogle Scholar

Copyright information

© Plenum Press, New York 1984

Authors and Affiliations

  • Deirdre McIntosh
    • 1
    • 2
  • Philip Thorpe
    • 1
    • 2
  1. 1.Chester Beatty LaboratoriesInstitute of Cancer ResearchLondonUK
  2. 2.Imperial Cancer Research FundLondonUK

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