The preparation of monoclonal antibodies against AAV2 and study on their characterizations / 病毒学报

7 strains of stable cell lines secreting monoclonal antibodies against AAV2 capsids were obtained by immunizing BALB/C mice with highly purified recombinant adeno-associated virus. Among them, the monoclonal antibodies B10 and G4 had neutralizing activity, and their subtypes were IgG1 and IgG2a, respectively. The binding characterizations of the two neutralizing antibodies were studied. Both B10 and G4 showed serotype specific binding activities to rAAV2 virus particles other than AAV1, AAV5, and AAV8, and the binding could not be blocked by heparin. After incubating with the two antibodies separately, rAAV2 viruses could still bind to sensitive cell line BHK-21, suggesting that the binding sites of the two antibodies to rAAV2 located at different positions on viral particle surface from the primary receptor binding sites of AAV2. Western blotting assay showed that B10 could bind to VP1, VP2 and VP3 of rAAV2. However, G4 bound none of them. The results suggested that B10 recognized a linear epitope of AAV2 capsid, whereas G4 probably recognized a conformational epitope on the surface of AAV2 virus particle. The two antibodies with different characteristics provided valuable tools for AAV2 virus particles detection and infection processes.

Transfection efficiency of adenoviral vector AD5/F35 to malignant hematopoietic cells of different origins / 中国实验血液学杂志

This study was aimed to investigate the transfection efficiency of adenoviral vector AD5/F35 to hematopoietic malignant cells lines of various origins and AD5/F35 cytotoxicity. The hematologic malignant cell lines of various origins were transfected by AD5/F35-EGFP at different multiple of infection (MOI) and AD5-EGFP was used as control; the proportion of fluorescence positive cells was detected by flow cytometry; the killing effect of virus on infective target cells was assayed by MTT and observed by fluorescence microscopy. The results showed that the transfection efficiency of AD5/F35 vector to cell line of myeloid origin was > 99% at MOI = 30, the transfective efficiency of AD5 vector was 26.4% at MOI = 1,000; the transfection efficiency of AD5/F35 vector and AD5 vector to cell line of B cell origin were 11.7% and 5.7%, respectively, at MOI = 1,000. AD5/F35 and AD5 vectors could not effectively transfect cells of T cell origin, no fluorescence positive cells were detected at MOI = 1,000; no significant killing effect of AD5/F35 vector on infective target cells was observed at MOI = 1,000. It is concluded that AD5/F35 vector infection has definite selectivity to hematologic malignant cells of various origin, the infection ability of AD5/F35 vector to cells of myeloid origin is stronger than that to cells of B cell origin, the cytotoxicity of AD5/F35 vector to infective target cells is small. The AD5/F35 vector is preferable to AD5 vector in respect of infection ability and offers good prospects of application in gene therapy for myeloid leukemia cells as target cells.

Generation of human recombinant antibody Fab fragment and its IgG to adeno-associated virus type II from phage display library / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To acquire the recombinant human monoclonal antibodies and IgG to adeno-associated virus type 2 (AAVs-2).</p><p><b>METHODS</b>Construct and pan human Fab antibody library to AAVs-2 was established from normal volunteer donors by using phage display technology and secreted expression in E.Coli system. The positive Fab clones were selected and characterized through ELISA and immunofluorescent assay, and then the heavy and light chain were sequenced. The gene of light chain and heavy chain Fd fragment of recombinant mAb were inserted into baculovirus expression vector pAC-L-Fc and construct expression vectors of intact IgG, then transfected insert sf-9 cell secreted expression in Baculovirus/Insert system. Immunoprecipitation test was used to detect its recognizing region.</p><p><b>RESULTS</b>One clone named AAVs-31 showed positive responses in ELISA and IFA, the Fab was composed of gamma chain and kappa chain IgG was positive in ELISA and IFA. The IgG failed to detect nonassembled or denatured capsid proteins, but recognized the AAVs-2 stock from immunoprecipitation test.</p><p><b>CONCLUSION</b>The authors isolated a clone of Fab and IgG to adeno-associated virus type 2 by phage display technology, they perhaps recognize an epitope which is formed during capsid assembly.</p>

Construction of a tRNAVal promoter plasmid expressing shRNAs in mammalian cells which mediates RNA interference / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>Constructing a plasmid containing tRNAVal promoter to express shRNA which mediates RNA interference.</p><p><b>METHODS</b>A tRNAVal gene was amplified from human genomic DNA by PCR and replaced the last several bases of 3' end by a linker. The tRNAVal promoter after artificial mutation followed a shRNA sequence to luciferase was cloned into pUC18, Puc-tRNAVal, lucRi Cotransfected with pMAMneoLuc into BHK-21 cell to detect the effect of luciferase expression.</p><p><b>RESULTS</b>pUC-tRNAVallucRi suppressed the luciferase expression from pMAMneoLuc by 97.9%-9.5%.</p><p><b>CONCLUSION</b>The results showed that the tRNAVal shRNA plasmid could efficiently suppress luciferase expression in BHK-21.</p>