New Indirect Approach to the Therapeutic Use of Immunotoxins
- 18 May 1988
- journal article
- research article
- Published by Oxford University Press (OUP) in JNCI Journal of the National Cancer Institute
- Vol. 80 (6), 439-443
- https://doi.org/10.1093/jnci/80.6.439
Abstract
To improve the applicability of immunotoxins (ITs), we have developed a new two-step indierct procedure. The target cells to be killed are first incubated with cell-specific mouse monoclonal antibodies (MAbs). After removal of excess unbound antibody, the cells are incubated in the presence of lactose with an indirect IT, a conjugate of whole abrin and sheep antimouse immunoglobulin (SAM) that binds only to cells having primary mouse MAbs on their surfaces. The SAM-abrin IT is affinity purified before use to remove molecules with exposed B-chain-binding sites; it was nontoxic in the absence of the specific mouse MAbs, demonstrating the specificity of the two-step method. We compared the indirect approach, using four different primary MAbs, with the conventional method, in which abrin is coupled directly to the mouse MAbs. In three human cell lines—the melanoma line FEMX, the Burkitt cell line Rael, and the leukemia cell line KM3—the cell kill, measured by a clonogenic assay, was consistently greater with the indirect than with the direct method. In the melanoma and Rael cells, the indirect method gave a higher cell kill than even native abrin. With a mixture of two different antibodies an additive effect was observed with the indirect but not with the direct method. The new approach greatly simplifies the therapeutic application in vitro of ITs, because it permits theuse of different primary antibodies, singly or inmixtures, in conjunction with only one or a few general indirect ITs. In efforts to further improve the usefulness of the indirect method, other indirect ITs containing different toxin moieties are being examined. The possibility of employing the indirect principle in vivo is being explored. [J Natl Cancer Inst 1988;80;439–443]This publication has 12 references indexed in Scilit:
- RAPID SCREENING WITH INDIRECT IMMUNOTOXIN FOR MONOCLONAL-ANTIBODIES AGAINST HUMAN SMALL-CELL LUNG-CANCER1987
- An ineffective monoclonal antibody-ricin A chain conjugate is converted to a tumouricidal agent in vivo by subsequent systemic administration of ricin B chainCancer Immunology, Immunotherapy, 1987
- Human Melanoma Cell Lines Showing Striking Inherent Differences in Sensitivity to Immunotoxins Containing Holotoxins2JNCI Journal of the National Cancer Institute, 1986
- Magnetic microspheres and monoclonal antibodies for the depletion of neuroblastoma cells from bone marrow: Experiences, improvements and observationsBritish Journal of Cancer, 1986
- Synergy between immunotoxins prepared with native ricin A chains and chemically-modified ricin B chains.The Journal of Immunology, 1986
- Cloned fragment of diphtheria toxin linked to T cell-specific antibody identifies regions of B chain active in cell entry.Journal of Biological Chemistry, 1986
- EVALUATION OF MONOCLONAL-ANTIBODIES FOR THE DEVELOPMENT OF BREAST-CANCER IMMUNOTOXINS1985
- Blockade of the galactose‐binding sites of ricin by its linkage to antibodyEuropean Journal of Biochemistry, 1984
- Kinetics of protein synthesis inactivation by ricin-anti-Thy 1.1 monoclonal antibody hybrids. Role of the ricin B subunit demonstrated by reconstitution.Journal of Biological Chemistry, 1982
- In vitro sensitivity of human melanoma xenografts to cytotoxic drugs. Correlation within vivo chemosensitivityInternational Journal of Cancer, 1980