An efficient method of sorting liver stem cells by using immuno-magnetic microbeads

AIM： To develop a method to isolate liver stem cells fast and efficiently. METHODS： Fetal mouse liver cells were characterized by cell surface antigens （c-Kit and CD45/TER119） using flow cytometry. The candidate liver stem cells were sorted by using immuno-magnetic microbeads and identified by -lone-forming culture, RT-PCR and immunofluorescence says. RESULTS： The c-Kit-（CD45/TER119）- cell population with 97.9% of purity were purified by immuno-magnetic microbeads at one time. The yield of this separation was about 6% of the total sorting cells and the cell viability was above 98%. When cultured in vitro these cells had high clone-forming and self-renewing ability and expressed markers of hepatocytes and bile duct cells. Functionally mature hepatocytes were observed after 21 d of culture. CONCLUSION： This method offers an excellent tool for the enrichment of liver stem cells with high purity and viability, which could be used for further studies. It is fast, efficient, simple and not expensive.

Preparation of Immuno-magnetic Beads and Their Separation & Detection to Ovary Cancer Cells

The organic monomer-molecule with nanometer magnetic powder by means of reforming the surface of nanometer magnetic powder have been synthesized. Magnetic beads in diameter of 2 mum or so am obtained by controlling conditions. Ovary cancer cells of ascites are separated and ovary cancer cells of blood arc detected by using immuno-magnetic beads linked with ovary cancer cell mono-antibodies. Results show that the specificity is 85% sensitivity is 87%, accuracy is 84%, cells acquiring purity is 90%, cells activity is 92% and detection sensitivity is 25 x 10(-7).

Applications of immuno-magnetic bead and immunofluorescent flow cytometric techniques for the quantitative detection of HAB microalgae

Overthelastseveraldecades,harmfulalgalblooms(HABs)havebecomeaseriousenvironmental problem in many parts of the world. A rapid and accurate detection process for HAB algae has yet to be developed. Heterosigma akashiwo is one of the most important HABs species in China. The objective of this study was to develop an immunologic technique that can rapidly and sensitively count H. akashiwo cells. Five HABs species (Alexandrium catenella, Thalassiosira sp., Cryptomonas sp., Alexandrium tamarense and Symbiodinium sp.,) were used in this study to evaluate the analysis process we developed. A polyclonal antibody with high titers against H. akashiwo was obtained by injecting H. akashiwo cells into rabbits. Immuno-magnetic beads (IMB) were produced via conjugated polyclonal antibodies with magnetic beads and applied to isolate and count H. akashiwo cells from the culture. Results show that 66.7%-91.6% of the cells were captured from unialgal culture by IMBs, and only 5.3%-12.5% of the four other HAB microalgae species were captured, indicating that the constructed IMBs combined specifically with the H. akashiwo cells. At the same time, flow cytometry (FCM) sorting was exploited to screen H. akashiwo cells after labeling with FITC conjugated polyclonal antibodies. Using the FCM technique, 91.7% of the targeted cells were sorted out from mixed microalgae samples in just a few minutes. These results indicate that both antibody-involved IMB and antibody-based FCM techniques are highly effective at detecting and quantifying HAB species. These techniques, especially immuno-magnetic separation, have low associated cost, and are fast and simple processes compared with other techniques currently in use.

Usefulness of Immuno-Magnetic Beads Conjugated with Anti-EpCAM Antibody for Detecting Endometrial Cancer Cells

A simple and non-invasive method for detecting endometrial cancer in women with abnormal uterine bleeding is required. For this purpose, we prepared immuno-magnetic beads conjugated with anti-human EpCAM rat monoclonal antibody (mAb) for isolating exfoliated endometrial cells including endometrial cancer cells in vaginal discharge. The affinities of the anti-human EpCAM rat mAbs were analyzed by flow cytometry and immunocytochemistry and then magnetic beads were conjugated with the mAbs. The rate of retrieval of endometrial cells using the immuno-magnetic beads was calculated. Endometrial cells were isolated using the immuno-magnetic beads from the vaginal discharges of 22 patients with endometrial cancer and 16 non-malignant controls. The isolated cells were stained using endometrial cancer specific-mAbs and analyzed by flow cytometry and imaging cytometry. The immuno-magnetic beads conjugated with high-affinity mAb (clone 1456) appeared to have very low auto-fluorescence. Sufficient enrichment of Ep-CAMpositive cells using immuno-magnetic beads was observed in both simulation and clinical samples. The overall sensitivities of flow cytometry and imaging cytometry to detect endometrial cancer cells were 72.7% and 45.5%, respectively. Meanwhile, the overall specificities of flow cytometry and imaging cytometry for healthy controls were 75.0% and 81.3%, respectively. Our immuno-magnetic beads have very low auto-fluorescence, so they could be useful for fluorescent analysis, such as fluorescent immunochemical staining. In the future, these novel immuno-magnetic beads could be used for cytological study.

Hepatocytes isolated from neoplastic liver-immunomagnetic purging as a new source for transplantation

AIM： To investigate whether hepatocytes isolated from macroscopically normal liver during hepatic resection for neoplasia could provide a novel source of healthy hepatocytes, including the development of reliable protocols for malignant cells removal from the hepatocyte preparation. METHODS： Hepatocytes were procured from resected liver of 18 patients with liver tumors using optimised digestion and cell-enrichment protocols. Suspensions of various known quantities of the HT-29 tumor cell line and patient hepatocytes were treated or not with Ep-CAM-antibody-coated immunomagnetic beads in order to investigate the efficacy of tumor-purging by immunomagnetic depletion, using a semi-quantitative RT-PCR method developed to detect tumor cells. Immunomagnetic bead-treated or bead-untreated tumor cell-hepatocyte suspensions were transplanted intra-peritoneally in Balb/C nude mice to assess the rates of tumor development. RESULTS： Mean viable hepatocyte yield was 9.3×10^6 cells per gram of digested liver with mean viability of 70.5%. Immunomagnetic depletion removed tumor cells to below the RT-PCR detection-threshold of 1 tumor cell in 10^6 hepatocytes, representing a maximum tumor purging efficacy of greater than 400000-fold. Transplanted, immunomagnetic bead-purged tumor cell-hepatocyte suspensions did not form peritoneal tumors in Balb/C nude mice. Co-transplantation of hepatocytes with tumor cells did not increase tumorigenesis of the tumor cells. CONCLUSION： Immunomagnetic depletion appears to be an effective method of purging contaminating tumor cells to below threshold for likely tumorigenesis. Along with improved techniques for isolation of large numbers of viable hepatocytes, normal liver resected for neoplasia has potential as another clinically useful source of hepatocytes for transplantation.