• Archives of Pharmacal Research
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• v.16 no.4
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• pp.347-348
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• 1993

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.98-104
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• 1995

Recently murine monoclonal antibodies have been studied actively for radioimmuno-scintigraphy and radioimmunotherapy, especially on patients with leukemia and lymphoma. In this research, we studied radiolabeling and immunologic characteristics of two in-house anti-leukemic monoclonal antibodies(anti-CALLA & anti-JL-1 antibodies) to make the basis for their clinical application. Each antibody was radiolabeled successfully with $^{99m}Tc$ by pretargeting transchelation method and with $^{125}I$ by lodogen method. We also studied cell binding assay, Scatchard analysis and modulation phenomenon. $^{125}I$ showed 90% labeling efficiency for each anti-body which was satisfactory, but $^{99m}Tc$ showed labeling efficiency below 70%, for which we need better labeling method. In cell binding assay, the immunoreactivity(IR) was low for $^{99m}Tc$-labeled antibodies. Scatchard analysis showed satisfactory data for both binding affinity. The affinity constant and antibody binding sites per cell are around $10^9M^{-1}$ and $10^4$, respectively. There was no modulation phenomenon in cases of $^{125}I$ or $^{99m}Tc$ labeled antibodies. We expect that two anti-leukemic monoclonal antibodies may be useful in diagnosis and therapy for leukemia and lymphoma patients.

• Archives of Pharmacal Research
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• v.17 no.6
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• pp.452-457
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• 1994

The water soluble long-chain crosslinker, sulfo-succinimidyl-6-[3'-(2-pyridyldithio)-propion-amido]hexanoate (S-LC-SPDP) was used to prepare ricin A chain (RAT) immunotoxins constructed with whole igG and Fab fragments of the anti-common acute lymphoblastic leukemiz antigen (CALLA)monoclonal antibody. In this study, a) S-LC-SPDP modification efficiencies immunoreactivity and cytotoxicity of immunotoxins constructed were examined. IgG-RTA and Fab-RTA immunotoxins were prepared with 67.3% and 57.0% conjugation yields, respectively. These long spacer intemolecular linked immunotoxins were selectively immunoreactive and to antigen K562 cells. Both IgG-RAT and Fab-RAT immunotoxins were 210-and 45-fold more active than intavt RAT in vitro, respectively.

• Archives of Pharmacal Research
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• v.22 no.5
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• pp.459-463
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• 1999

The effects of the hindered and non-hindered water soluble long-chain disulfide bonds on the stability and cytotoxicity of the ricin A chain (RTA) immunotoxin were examined. The RTA immunotoxins were prepared with the Fab fragments of anti-common acute lymphoblastic leukemia antigen (CALLA) monoclonal antibody (Fab-RTA) using sulfosuccinimidyl-6-[(-methyl-(-2-pyridyldithio)toluamido]toluamido]hexanoate (S-LC-SMPT) and sulfosuccinimidyl-6-[3-(2-pyridyldithio-propionamido]hexanoate (S-LC-SPDP). The prepared Fab-RTA immunotoxins were evaluated for their conjugation yield, immunoreactivity, thermal and disulfide bond stability and cytotoxicity. The conjugation yield of the Fab-RTA immunotoxin from the water soluble long chain crosslinking agents, S-LC-SMPT and S-LC-SPDP, were comparable. Both Fab-RTA immunotoxins exhibited a similar immunoreactivity and thermal stability in aqueous solution. However, S-LC-SMPT -mediated Fab-RTA, sterically hindered, showed an enhanced disulfide bond stability in vitro over S-LC-SPDP mediated one. In the cytotoxicity against antigenic cell Daudi, the S-LC-SMPT -mediated RTA immunotoxin maintained a comparable cytotoxicity, compared with S-LC-SPDP mediated Fab-RTA immunotoxin.