Development of a Novel AAV Serotype Vector for Human Targeted Liver

In recent years, the number of clinical trials of adeno-associated virus (AAV) vectors for gene transfer in vivo has steadily increased. Excellent safety and efficient transduction of a wide range of target tissues make AAV vectors to be the platform of choice for gene therapy in vivo. However, due to the poor selectivity of AAV vector serotypes and target cells, the presence of AAV neutralizing antibodies and the continuous occurrence of immune responses, the effect of gene therapy is seriously affected. DNA shuffling was employed to produce an AAV cap gene library based on eight different AAV (AAV1—AAV4, AAV6—AAV9) capsid genes. DNA sequences in the mutant gene library were inserted into the plasmid containing the AAV2 Rep gene and the ITR sequence, and the resulting plasmid (pIRC) has a full set of AAV genomic sequences.The purified virus was collected after co-transfection with HEK 293 cells for 72 h hours to obtain an AAV mutant library. Human liver cancer Hep G2 cells were assisted by wild type 5 adenovirus (wt Ad5). After screening, we finally obtained a capsid protein mutant AAVXL12 in hepatocytes. By infecting Hep G2 cells with different serotypes of recombinant AAV virus carrying the GFP gene, we observed different degrees of green fluorescence expression, which finally showed that the serotype vector AAVXL12 mediated GFP gene expression was the best. Therefore, the new AAV vector, which is highly infectious to human liver cells, has enhanced the efficiency of gene transduction and is expected to provide a novel therapeutic vector for AAV for gene therapy.