RT Journal Article SR Electronic(1) A1 Zhang, Xiaoliu A1 O′Shea, Helen A1 Entwisle, Clare A1 Boursnell, Mike A1 Efstathiou, Stacey A1 Inglis, StephenYR 1998 T1 An efficient selection system for packaging herpes simplex virus amplicons JF Journal of General Virology, VO 79 IS 1 SP 125 OP 131 DO https://doi.org/10.1099/0022-1317-79-1-125 PB Microbiology Society, SN 1465-2099, AB Due to their simplicity and flexibility of genomic construction, herpes simplex virus (HSV) amplicon- based vectors are attractive vehicles for gene delivery. However, a significant problem faced in the generation of amplicon stocks is the low amplicon to helper virus (A/H) ratio. In order to improve the proportion of amplicons generated, a selection system for amplicon production was developed in which the HSVthymidine kinase (TK) gene is inserted into an amplicon plasmid and an HSV mutant with both TK and glycoprotein H (gH) genes deleted is used as a helper virus. Using a protocol in which amplicon stocks are passaged 2–3 times in BHK cells of TK and gH genotype in the presence of selection medium containing methotrexate, stock preparations with high A/H ratio (up to 5:1) and high amplicon titre (> 1 × 109 infectious units/ml) were generated. In vitro characterization demonstrated that a high level of biologically functional products can be efficiently produced from these amplicon constructs., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-79-1-125