Specific capture and determination of glycoprotein using a hybrid epitopes and monomers-mediated molecular-imprinted polymer enzyme-free electrochemical biosensor.

A novel molecular-imprinted polymer (MIP)-based enzyme-free biosensor was created for the selective detection of glycoprotein transferrin (Trf). For this purpose, MIP-based biosensor for Trf was prepared by electrochemical co-polymerization of novel hybrid monomers 3-aminophenylboronic acid (M-APBA) and pyrrole on a glassy carbon electrode (GCE) modified with carboxylated multi-walled carbon nanotubes (cMWCNTs). Hybrid epitopes of Trf (C-terminal fragment and glycan) have been selected as templates. The produced sensor exhibited great selective recognition ability toward Trf under optimal preparation conditions, offering good analytical range (0.125-1.25 µM) with a detection limit of 0.024 µM. The proposed hybrid epitope in combination with hybrid monomer-mediated imprinting strategy was successfully applied to detect Trf in spiked human serum samples, with recoveries and relative standard deviations ranging from 94.7 to 106.0% and 2.64 to 5.32%, respectively. This study provided a reliable protocol for preparing hybrid epitopes and monomers-mediated MIP for the synergistic and effective determination of glycoprotein in complicated biological samples.

[Effect of esculentoside A on cellular adhesion].

AIM: To investigate the anti-inflammatory mechanism of esculentoside A (EsA) and to observe the effects of EsA on cellular adhesion between human umbilical vein endothelial cell (VEC304) and human neutrophil and to further observe the mRNA expression of intercellular adhesion molecule-1 (ICAM-1) and cluster of differentiation 18(CD18). METHODS: The hemocyte counting method was used for assaying the adhesion rate between VEC304 and neutrophil. The RT-PCR method was used for measuring the mRNA expression of ICAM-1 and CD18. RESULTS: The adhesion rate between VEC304 and neutrophil was increased with treatment of lipopolysaccharide(LPS). EsA (3 - 12 x 10(-6) mumol.L-1) was shown to inhibit the high cellular adhesion induced by LPS. A further investigation of adhesion molecules mRNA expression was undertaken using semi-quantitative reverse transcribed polymerase chain reaction (RT-PCR). The results of RT-PCR from VEC304 and human neutrophil treating with LPS showed that ICAM-1 and CD18 mRNA expressions were higher than those of normal cells, while this increased expression of ICAM-1 and CD18 mRNA was remarkably attenuated by the addition of EsA. CONCLUSION: EsA was found to inhibit the increased adhesion rate induced by LPS. Moreover, LPS induced high expression of ICAM-1 and CD18 was inhibited with treatment of EsA. It might be involved in the mechanisms of anti-inflammation of EsA.

Effect of esculentoside A on autoimmunity in mice and its possible mechanisms.

AIM: To investigate the influence of esculentoside A (EsA) on autoimmunity in mice and its possible mechanisms. METHODS: The level of anti-ds DNA antibody, proliferation of lymphoid cells, and inflammation by pathologic section of joint in mice were examined. The autoimmunity model is made through immunizing mice with formaldehyde treated Campylobacter jejuni strain CJ-S131 and Freund's complete adjuvant. The apoptosis of T cell was analyzed through morphology and flow cytometry (FACS). The expression of ICAM-1 mRNA in human umbilical vein endothelial cell line (ECV304) was determined by coupled reverse transcription and PCR amplification (RT-PCR). RESULTS: EsA could potently lower the level of anti-ds DNA antibody, inhibit the proliferation of lymphoid cells, and ameliorate inflammation in the joint of model mouse. The apoptosis of thymocyte activated by ConA was markedly accelerated while the expression of ICAM-1 mRNA in ECV304 was decreased by EsA. CONCLUSION: EsA has the positive curative effect on autoimmunity in a mouse model, which may function through inhibition of expression of ICAM-1 mRNA in ECV304 and acceleration of thymocyte apoptosis.

Effects of esculentoside A on production of interleukin-1, 2, and prostaglandin E2.

AIM: To investigate the influence of esculentoside A (EsA) on immunological function and its mechanism of anti-inflammation. METHODS: Interleukin-1 production was measured by thymocyte co-stimulating assay; the radioactivity of [(3)H]arachidonic acid (AA) was used to evaluate the release of AA; prostaglandin E2 production was measured with radioimmunoassay (RIA); IL-2 and IFN-gamma were detected by ELISA method. RESULTS: EsA (3-12 micromol/L)could potently inhibit the production of IL-1 and PGE(2) from both silent and LPS induced macrophages. EsA had no significant effect on the release of AA from murine macrophages. EsA could inhibit the production of IL-2 from murine lymphocytes induced by ConA, but not affect the production from silent lymphocytes. EsA showed no effect on the production of IFN-gamma from both silent and ConA induced lymphocytes. CONCLUSION: EsA could affect the immunological function through inhibiting the production of IL-2 from activated splenocytes and the inhibition of production of IL-1 and PGE(2) might be one of the anti-inflammation mechanisms of EsA.