Shear-induced release of disabled herpes simplex virus from baby-hamster kidney cells

A new process route is proposed to increase the production yield of disabled herpes simplex virus type 1 (HSV-1 DIS). Infected baby-hamster kidney (BHK) cells were subjected to a range of shear rates between 3.69 x 10(3) s(-1) and 51.3 x 10(3) s(-1) in the gap between a pair of co-axial cylinders. Analysis of the supernatant fractions of sheared material established that optimal virus release was achieved by exposing the infected cells to a shear rate of 42.7 x 10(3) s(-1) for a period of 1 min. Compared with the current laboratory process, the titre of HSV-1 DIS was increased over 30-fold, from about 1 x 10(6) to 30 x 10(6) pfu (plaque-forming units)/ml. Evaluation of the supernatant fractions by flow cytometry, total protein assay, PAGE and dot-blot assays showed no evidence of cell disruption, supporting the hypothesis that shear-induced release of the cell-membrane-bound virus was achieved without compromising downstream purification. The proposed method is scalable, and since no additional chemicals are required, it provides an attractive option for enhanced recovery of virus particles for therapeutic applications.