In vivo Evaluation of Human Embryonic Stem Cells Isolated by 57-C11 Monoclonal Antibody

BACKGROUND: The normal cells derived from human embryonic stem cells (hESCs) are regarded as substitutes for damaged or dysfunctional adult cells. However, tumorigenicity of hESCs remains a major challenge in clinical application of hESC-derived cell transplantation. Previously, we generated monoclonal antibody (MAb) 57-C11 specific to the surface molecule on undifferentiated hESCs. The aim of this study is to prove whether 57-C11-positive hESCs are pluripotent and tumorigenic in immunodeficient mice. METHODS: Undifferentiated hESCs were mixed with retinoic acid (RA)-differentiated hESCs at different ratios prior to 57-C11-mediated separation. To isolate 57-C11-positive hESCs from the mixture, biotinylated 57-C11 and streptavidin-coated magnetic beads were added to the mixture. Unbound 57-C11-negative hESCs were first isolated after applying magnet to the cell mixture, and 57-C11-bound hESCs were then released from the magnetic beads. In order to measure the efficiency of separation, 57-C11-positive or -negative hESCs were counted after isolation. To evaluate the efficiency of teratoma formation in vivo, 57-C11-positive or negative cells were further injected into left and right, respectively, testes of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. RESULTS: Approximately 77~100% of undifferentiated hESCs were isolated after applying 57-C11-coated magnetic beads to the mixed cell populations. Importantly, teratomas were not observed in NOD/SCID mice after the injection of isolated 57-C11-negative hESCs, whereas teratomas were observed with 57-C11-positive hESCs. CONCLUSION: 57-C11-positive hESCs are pluripotent and tumorigenic. The combination of 57-C11 and magnetic beads will be useful to eliminate remaining undifferentiated hESCs for the safe cell transplantation.

In vivo hepatitis B virus-neutralizing activity of an anti-HBsAg humanized antibody in chimpanzees

Previously, we constructed a humanized antibody (HuS10) that binds to the common a antigenic determinant on the S protein of HBV. In this study, we evaluated its HBV-neutralizing activity in chimpanzees. A study chimpanzee was intravenously administered with a single dose of HuS10, followed by intravenous challenge with the adr subtype of HBV, while a control chimpanzee was only challenged with the virus. The result showed that the control chimpanzee was infected by the virus, and thus serum HBV surface antigen (HBsAg) became positive from the 14th to 20th week and actively acquired serum anti-HBc and anti-HBs antibodies appeared from the 19th and 23rd week, respectively. However, in the case of the study chimpanzee, serum HBsAg became positive from the 34th to 37th week, while actively acquired serum anti-HBc and anti-HBs antibodies appeared from the 37th and 40th week, respectively, indicating that HuS10 neutralized the virus in vivo and thus delayed the HBV infection. This novel humanized antibody will be useful in the immunoprophylaxis of HBV infection.

Rebamipide Protects Colonic Damage Induced by Trinitrobenzene Sulfonic Acid (TNBS) via Down-Regulation of TNF-alpha IL-1beta and ICAM-1 / 대한해부학회지

During inflammation of the colon, cells of the gut mucosa produce or express numerous inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1 beta), and intercellular adhesion molecule 1 (ICAM-1). These mediators have been implicated as contributory factors to the inflammatory process, which results in colitis during inflammatory bowel disease (IBD). Rebamipide is an anti-gastric ulcer drug with anti-inflammatory properties in vivo and in vitro. The effects of Rebamipide on IBD have not been largely evaluated. Therefore, this study investigated the potential of Rebamipide to regulate the production of inflammatory mediators such as TNF-alpha, IL-1beta, and ICAM-1. Mice with trinitrobenzene sulfonic acid (TNBS)-induced colitis (IBD animal model), were treated intrarectally with 2 mM Rebamipide. Body weight, macro- and micro-histological scores, and activity were evaluated. As an index of tissue edema, the thickness of the colonic wall was measured between the serosal surface and the luminal surface of the mucosa. TNF-alpha, IL-1 beta, and ICAM-1 were detected by immunohistochemical staining. Rebamipide treatment of mice exhibiting TNBS-induced colitis dramatically improved the clinical and histopathological findings of inflammation. In addition, Rebamipide suppressed TNF-alpha, IL-1 beta, and ICAM-1 expression in TNBS-treated animals. Taken together, these findings suggest that Rebamipide is a potential therapeutic agent for treating patients with IBD.