Prokaryotic expression of a recombinant protein of adeno-associated virus capsid conserved regions and preparation of its polyclonal antibody / 南方医科大学学报

OBJECTIVE@#To express and purify the antigenic peptide of adeno-associated virus (AAV) capsid conserved regions in prokaryotic cells and prepare its rabbit polyclonal antibody.@*METHODS@#The DNA sequence encoding the conserved regions of AAV capsid protein was synthesized and cloned into the vector pET30a to obtain the plasmid pET30a-AAV-CR for prokaryotic expression and purification of the conserved peptides. Coomassie blue staining and Western blotting were used to identify the AAV conserved peptides. Japanese big ear white rabbits were immunized with AAV conserved region protein to prepare polyclonal antibody, with the rabbits injected with PBS as the control group. The antibody titer was determined with ELISA, and the performance of the antibody for recognizing capsid protein sequences of AAV1-AAV10 was assessed with Western blotting and immunofluorescence assay.@*RESULTS@#The plasmid pET30a-AAV-CR was successfully constructed, and a recombinant protein with a relative molecular mass of 17000 was obtained. The purified protein induced the production of antibodies against the conserved regions of AAV capsid in rabbits, and the titer of the purified antibodies reached 1:320 000. The antibodies were capable of recognizing a wide range of capsid protein sequences of AAV1-AAV10.@*CONCLUSION@#We successfully obtained the polyclonal antibodies against AAV capsid conserved region protein from rabbits, which facilitate future studies of AAV vector development and the biological functions of AAV.

Relationship between serum vasoactive factors and plaque morphology in patients with non-ST-segment elevated acute coronary syndrome / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Vasoactive factors have been reported to correlate with vulnerable plaque and acute coronary syndrome (ACS). This study aimed to investigate the relationship between vasoactive factors and plaque morphology in patients suffering from non-ST-segment elevated ACS.</p><p><b>METHODS</b>From April 2007 to April 2009, 124 consecutive patients suffering from non-ST-segment elevated ACS who had received coronary angiography (CAG) and intravascular ultrasound (IVUS) in the People's Liberation Army General Hospital and Beijing Anzhen Hospital were enrolled in this study. Three serum vasoactive factors, plasma soluble vascular endothelial growth factor receptor-1 (sFlt-1), placental growth factor (PLGF) and interleukin-18 (IL-18), were measured by enzyme-linked-immunosorbent serologic assay of the patients. The levels of vasoactive factors were compared between vulnerable plaque group and stable plaque group, and between unstable angina pectoris (UAP) group and non-ST-segment elevation acute myocardial infarction (NSTE-AMI) group. The relationship between the plaque morphology and levels of vasoactive factors was analyzed.</p><p><b>RESULTS</b>The levels of vasoactive factors were similar between the UAP group (69 patients) and NSTE-AMI group (55 patients). The levels of sFlt-1 and PLGF in the vulnerable plaque group were significantly higher than those in the stable plaque group. The level of IL-18 was correlated positively with plaque morphology. Multivariate Logistic regression analysis showed that the level of PLGF was an independent risk factor for vulnerable plaque (OR=2.115, 95% CI 1.415-5.758, P=0.018). Using the ROC curve, PLGF was a significant factor for the diagnosis of vulnerable plaque (the diagnostic point was 26.3 ng/L, the proportion of square area under the ROC curve was 0.799, 95%CI 0.758-0.839, P<0.001; the sensitivity of PLGF under the ROC curve was 86%, and the specificity 63%).</p><p><b>CONCLUSION</b>Both IL-18 and PLGF are biomarkers for vulnerable plaques and helpful to predict vulnerable plaque.</p>