• BMB Reports
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• v.55 no.3
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• pp.142-147
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• 2022

Human pluripotent stem cells (PSCs) have been utilized as a promising source in regenerative medicine. However, the risk of teratoma formation that comes with residual undifferentiated PSCs in differentiated cell populations is most concerning in the clinical use of PSC derivatives. Here, we report that a monoclonal antibody (mAb) targeting PSCs could distinguish undifferentiated PSCs, with potential teratoma-forming activity, from differentiated PSC progeny. A panel of hybridomas generated from mouse immunization with H9 human embryonic stem cells (hESCs) was screened for ESC-specific binding using flow cytometry. A novel mAb, K312, was selected considering its high stem cell-binding activity, and this mAb could bind to several human induced pluripotent stem cells and PSC lines. Cell-binding activity of K312 was markedly decreased as hESCs were differentiated into embryoid bodies or by retinoic acid treatment. In addition, a cell population negatively isolated from undifferentiated or differentiated H9 hESCs via K312 targeting showed a significantly reduced expression of pluripotency markers, including Oct4 and Nanog. Furthermore, K312-based depletion of pluripotent cells from differentiated PSC progeny completely prevented teratoma formation. Therefore, our findings suggest that K312 is utilizable in improving stem cell transplantation safety by specifically distinguishing residual undifferentiated PSCs.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.95-95
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• 1997

Among the various receptor molecules discovered so far the ${\beta}$2-adrenergic receptors have been regarded as excellent model systems for the so called 7 transmembrane helix receptor and have been the focus of extensive studies. For the analysis of receptor structure and function a monoclonal antibody plays a crucial role, thus providing useful tools for the study of receptor. However, because of the minute quantity of receptor molecules which could be obtained from natural sources, the generation of specific monoclonal antibody against receptor molecules from the purified receptors has been regarded as virtually impractical in consideration of cost and experimental times. The purpose of the present study was to generate and characterize a monoclonal antibody against human ${\beta}$2-adrenergic receptor. For the production of antibody, C-terminal regions of the human ${\beta}$2-adrenergic receptor was produced as a fusion protein with Glutathion S-transferase (GST) in E. Coli. The expression of the fusion protein was identified by SDS-PAGE and Western blot using monoclonal anti-GST antibody. The fusion protein was purified to an apparent homogeniety by affinity chromatography with Glutathion Sepharose CL-4B and used as an antigen for the immunization of BALB/C mice. The Production of monoclonal antibody was achieved by fusion of the immunized spleen cells and SP/2-0 myeloma cells. Positive hybridomas were screened by ELISA and were cloned by two consecutive rounds of limiting dilution. The monoclonal antibody produced in this study (mAb${\beta}$C02) was IgM type and purified by immunoaffinity chromatography using anti-mouse IgM agarose as an affinity matrix. MAb${\beta}$C02 showed strong and specific immunoreactivity against both the fusion protein and human ${\beta}$2-adrenergic receptor in ELISA and Western blot. The molecular weight of immunoreactive band was 64 kDa and exactly coincided with the previously reported molecular weight of ${\beta}$2-adrenergic recepters. The results of the present study suggest that mAb${\beta}$C02 may be used for the study of receptor function and regulation in normal or nonphysiological status.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.399-406
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• 1986

This study was performed to establish human plasmacytoma cell line as the partner cells for producing human hybridoma. Bone marrow cells from a multiple myeloma patient from Seoul National University Hospital, Korea were cultured and established as the cell line, named as HMC-BM4. HMC-BM4 cells were cultivated in RPMI 1640 media containing 8-azaguanine(8-AG; gradually increasing concentration from $1\;{\mu}g/ml$ to $20\;{\mu}g/ml$). 8-AG resistant cells were collected and cloned by limiting dilution. Each clone was divided and tested to die in hypoxanthine, aminopterine and thymidine (HAT) selection media. Finally one clone was selected and named as HMC-AR, which was sensitive to HAT selection media. HMC-AR cells showed typical morphology of plamacytoma in Wright staining. No cell formed the rosette with sheep erythrocytes. Surface membrane $\mu$ heavy chain was detected in 20% of HMC-AR cells and cytoplasmic $\mu$ heavy chain in 90% of them by direct immunofluorescent staining. Ia-like antigen was found in 90% of HMC-AR cells by indirect immunofluorescent staining using anti-Ia-like antigen monoclonal antibody, 1BD9-2. And about $1.0\;{\mu}g/ml$ of human $\mu$ heavy chain was detected in the 3-day culture supernatant of HMC-AR cells. 88% of cells contained 46 chromosomes. Mycoplasma was not detected in HMC-AR cells by Hoechst 33258 staining. This cell line would be used for making hybridomas secreting human monoclonal antibody.

• Parasites, Hosts and Diseases
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• v.31 no.2
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• pp.149-156
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• 1993

Monoclonal antibodies (Mabs) were produced against crude scolex extract of T solium metacestodes, and applied to ELISA-inhibition test for improving the specificity of serodiagnosis of human cysticercosis. Four hybridomas secreting species-specific anti- cysticercal Mabs (Cya-1, Cya-7, Cya-28 and Cya-31) were selected. Each Mab reacted on antigenic components of 25.5 kDa (Cya-1), 28 kDa (rcya-7), 87.5 kDa (Cya-281), and 12.5 kDa (Cya-31). IFA showed that Cya-1 was located at the calcium corpuscles, and Cya-7 at the loose connective tissue of T soLium metacestode scolex. Cya-28 and Cya-31 reacted on the tegument of the scolex. By conventional ELISA, 23 out of 28 (82.1%) cysticercosis patients were found serologically positive, but 1 out of 9 (11.1%) sparganosls cases and 6 out of 31 (19.4%) paragonlmiasis cases showed false positives. By ELISA-Inhibition test using species-specific anti-cysticercal Mab Cya-7, 19 out of 28 (67.9%) cystlcercosis cases were found serologically positive, but there were no false positives In other parasitic infections.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.335-342
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• 1988

An anion exchange chromatography was employed for the purification of mouse monoclonal antibodies from ascitic fluid and in vitro cultivation media. After cultivation of hybridomas, Alps 25-3, HCGK, A4W, and KW, producing IgG1, the culture supernatants were harvested by centrifugation, precipitated with 50-60％ ammonium sulfate, and dialyzed against 0.025 M Tris-HCI buffer (pH 8.2). Then the dialyzed samples were loaded into a DEAE-Trisacryl M anion exchange column. Monoclonal antibodies bound to the DEAE-Trisacryl M were eluted with 0.025 M Tris-HCI buffer (pH 8.2) containing 30-40 mM NaCl. In ammonium sulfate precipitation, the recovery of the monoclonal antibody was shown to be 90％ and 84％ from in vitro culture media containing 10％ and 2％ fetal bovine serum, respectively. On the other hand, the pretreatment by ultrafiltration enhanced the yield up to 91％ whereas the purity was lower than that by ammonium sulfate treatment. Subsequently, in the DEAE-Trisacryl M chromatographic separation, the purities and recoveries of all the monoclonal antibodies from both the in vitro culture supernatants and ascitic fluids were 70-80％ and 65％ respectively. The monoclonal antibody, Alps 25-3 could be further purified with a purity of 95％ through an immunoadsorbent chromatography.