Isolation of rabbit aqueous humor-derived exosomes and their immunosuppression function / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To isolate exosomes from rabbit aqueous humor and to investigate their immunosuppression function.</p><p><b>METHODS</b>Aqueous humor was collected from 40 New Zealand rabbits and exosomes were isolated by fractional separation and ultracentrifugation methods; the morphology was studied with electron microscopy. The immunosuppressive-related proteins of exosomes were detected with Western blotting; their inhibitory effect on ConA-induced proliferation of T lymphocyte was estimation with CCK-8 cells proliferation assay.</p><p><b>RESULTS</b>Eight milliliters of aqueous humor were collected from 40 New Zealand rabbits and 200 μg exosomes was yielded. Under electron microscope, the exosomes had typical structure of lipid bi-layer with a diameter of 50-100 nm. The results of Western blotting showed that these exosomes expressed Hsp70, CD9 and Alix but not Grp94, presenting a typical exosomes protein profile. Moreover, exosomes expressed high level of TGF-β and significantly inhibited the proliferation of T lymphocytes.</p><p><b>CONCLUSION</b>Immunosuppressive exosomes can be isolated from rabbit aqueous humor, which may be involved in immunotolerance of the eye.</p>

Preparation of monoclonal antibodies against human mesenchymal stem cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To prepare monoclonal antibodies (McAbs) against human mesenchymal stem cells (hMSCs) and to study their biological characteristics.</p><p><b>METHODS</b>BALB/C mice were immunized with pooled hMSCs. McAbs were prepared by hybridoma technique and their biological characteristics were analyzed by indirect immunofluorescence, immunohistochemistry and flow cytometry.</p><p><b>RESULT</b>Five hybridoma cell lines were successfully established, which secret McAbs specifically against hMSCs. Investigations showed that all these McAb reacted only to hMSCs and had no cross-reaction to other human cells, the relative affinities of 5 McAbs were 1x10(6) (ZUB1), 1x10(5) (ZUB4), 1x10(6) (ZUC3), ZUE12 (1x10(5)) and 1x10(5) (ZUF10), respectively. Isotype analysis showed that ZUB1, ZUE12, ZUF10 against the same isotype, while ZUC3, ZUB4 against other two different isotypes alone. Flow cytometric analysis showed that the positive expression rate of cultured hMSCs was 87.39% (ZUB1), 88.07% (ZUB4), 88.12% (ZUC3), 69.89% (ZUE12) and 83.67% (ZUF10).</p><p><b>CONCLUSION</b>The prepared five McAbs can specifically react against hMSCs, which can be used for selection and study of hMCSs.</p>

Construction of recombinant plasmid containing mouse vasoactive intestinal peptide gene and its expression in COS-7 cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To construct the eukaryotic expression plasmid containing mouse vasoactive intestinal peptide(VIP) gene with biological activities.</p><p><b>METHODS</b>VIP cDNA including the sequences of signal peptide was cloned from mouse thymus by RT-PCR, and then inserted into the mammalian expression vector pcDNA3.1 between Hind III and EcoR I restriction sites. COS-7 cells were transfected with pcDNA3. 1-VIP using liposome, the expression of VIP was identified by Western blot and ELISA. Supernatant of transfected cell culture was added to LPS-stimulated macrophages and the TNF-alpha production in cell medium was observed by ELISA.</p><p><b>RESULTS</b>The cloned VIP cDNA was confirmed by enzyme digestion and DNA sequencing. The expression of VIP was detected in the pcDNA3. 1-VIP transfected COS-7 cells by Western blot and ELISA. The VIP in culture supernatant potently inhibited TNF-alpha production by LPS-induced Macrophages in vitro.</p><p><b>CONCLUSION</b>The eukaryotic expression plasmid that expresses biological active murine VIP has been constructed successfully.</p>