Biomedical subjects

Ying-xun Sun

Publications and source records attributed to Ying-xun Sun.

4 recordsLinked to original sources

PubMed2006

[Cloning and expression of soluble B lymphocyte stimulator].

AIM: To clone and express soluble B lymphocyte stimulator (sBLyS). METHODS: Total RNA was isolated from peripheral blood mononuclear cells, and used to synthesize cDNA by reverse transcription. sBLyS cDNA was amplified by PCR with specific primers and inserted into a prokaryotic expression vector pET-30a. Recombinant plasmid was transformed into E.coli strain BL21(DE3). sBLyS was expressed in E.coli, purified in vitro, and analyzed with peptide mass fingerprinting and Daudi cell proliferation assay. RESULTS: sBLyS cDNA was cloned. Peptide mass fingerprinting of purified BLyS matched with that of BLyS proteins. Purified sBLyS could stimulate Daudi cell proliferation in vitro. CONCLUSION: sBLyS with biological activity was successfully expressed and purified.

Animals↗

PubMed2006

[Construction and expression of chimeric anti-human CD20 monoclonal antibody].

AIM: To construct the eukaryotic expression vector of chimeric anti-human CD20 monoclonal antibody (mAb) and realize its expression. METHODS: The light- and heavy-chain genes were amplified from hybridoma cell line 1-28 secreting anti-human CD20 mAb by RT-PCR and were cloned to T vector and sequenced. Proteins of mAb 1-28 were separated by reducing SDS-PAGE. Light- and heavy-chain bands were excised from preparative gel, digested by trypsin, and subjected to peptide mass fingerprinting. Software Biolynx and pepeseq were used to evaluate the score of probability. Correctness of the light- and heavy-chain DNA sequences was verified by their protein sequences. Genes of V(H) and V(L) were amplified from T vector and cloned into chimeric antibody expression vector (pCMV-V(H) and pCMV-V(L)), generating the expression vectors of chimeric anti-human CD20 mAb (C1-28) including light chain expression vector C1-28L and heavy chain expression vector C1-28H. The two plasmids were co-transfected into 293T cells with Lipofectamine 2000. RT-PCR was used to detect the transcription at mRNA level. C1-28 expression was detected by Sandwich ELISA and Western blot methods. RESULTS: mAb 1-28's genes were successfully cloned and verified by peptide mass fingerprinting. Eukaryotic expression vectors of anti-human CD20 mAb were constructed and expressed in 293T cells with the expression amount reaching 257 mg/L and the molecular weight consistent with that of human IgG. CONCLUSION: These experiments lay solid foundation for further study on the role of chimeric CD20 antibody in the treatment of non-Hodgkin's lymphoma.

Antibodies, Monoclonal↗

PubMed2005

[Experimental study of adoptive immunotherapy using CD3AK cells].

AIM: To analyze the immunological properties and biological activity of a monoclonal antibody (mAb) against CD3 molecule(yCD3), and to observe the tumor-suppressive activity of CD3AK cells in vitro and in vivo. METHODS: FCM was used to test the specificity of yCD3 and the immunological phenotype and cytokine production of CD3AK. 3H-TdR assay was used to measure the transformation of lymphocytes activated by yCD3. LDH assay was used to analyze the cytotoxic activity of CD3AK in vitro. Mice bearing tumors were used to observe the anti-tumor effect of CD3AK cells. RESULTS: yCD3 could bind specifically to T cells. 5 microg yCD3 could competitively inhibit 70% of standard anti-CD3 antibody to bind with CD3 molecules on cell membrane. 8 microg/L of yCD3 stimulated the proliferation of peripheral blood lymphocytes, which could be further boosted by IL-2 or anti-CD28 antibodies. Among activated CD3AK cells, CD3+, CD8+, and CD25+ cells increased. IL-2 and IFN-gamma producing CD3+ cells were also increased, to 3.29- and 2.47- fold, respectively, under the co-stimulation of anti-CD28 antibody. When the ratio of effective cells and target cells was 80:1, 57.54% target cells were killed. As compared with control, the percent of tumor inhibition in CD3AK cells treated tumor-bearing mice was 33.17%, and the inhibition rate of lung metastasis was 39.70%. The CD3AK cells treatment was more effective when combined with LAK cells. CONCLUSION: yCD3 could activate T cells and significantly induce the tumor-suppressive activity of CD3AK cells in vitro and in vivo, which lays a foundation for adoptive immunotherapy against tumors in clinical medicine.

Animals↗

PubMed2002

IL-6 inhibits apoptosis of human myeloma cell line XG-7 through activation of JAK/STAT pathway and up-regulation of Mcl-1.

BACKGROUND & OBJECTIVE: IL-6 can protect myeloma cells from apoptosis induced by various stimuli. A series of intracellular molecules might participate in this process. Our aim in this study is to investigate which anti-apoptotic Bcl-2 family proteins (Bcl-2, Bcl-XL, Mcl-1) and which signal transduction pathway(JAK/STAT, Ras/MAPK, PI-3K/Akt) can mediate the anti-apoptotic effect of IL-6 on a human myeloma cell line XG-7. METHODS: Apoptosis of XG-7 cells was analyzed by flow cytometry with propidium iodide(PI) staining of nuclei. The expression of three Bcl-2 family proteins in XG-7 cells were monitored by immunoblot assay. AG490, PD98059, and LY294002, three specific antagonists for JAK/STAT, Ras/MAPK, and PI-3K/Akt signal transduction pathways respectively, were used to determine which signal transduction pathway was responsible for the effect of IL-6 on XG-7 cells. RESULTS: IL-6 inhibited the apoptosis of XG-7 cells and up-regulated the expression of only one of the three anti-apoptotic Bcl-2 family proteins-Mcl-1. In addition, up-regulation of Mcl-1 expression induced by IL-6 was significantly inhibited in the presence of AG490, while not of PD98059 and LY294002. CONCLUSIONS: IL-6 inhibited apoptosis of XG-7 cells through up-regulation of Mcl-1 and the activation of JAK/STAT rather than Ras/MAPK nor PI-3K/Akt signal transduction pathway.

Apoptosis↗