A technique for determining the shear sensitivity of mammalian cells in suspension culture

A murine hybridoma was subjected to constant shear rates within a couette viscometer for periods of 15 hours. Shear effects on cells were determined by live cell counts, cell viability and by the release of the cytoplasmic enzyme lactate dehydrogenase into the culture medium. Cell damage was observed at a shear rate of 870s-1 but not at 420s-1

Experience in scale-up of homogeneous perfusion culture for hybridomas

A perfusion system for production of monoclonal antibodies was developed using an externally-mounted, hollow-fibre cartridge. The experimental apparatus was operated for 420 h and demonstrated increased steady-state viable cell concentration with increase in perfusion rate. Antibody titres were up to three times those measured for batch cultures and specific antibody productivity was doubled. The procedure was successfully scaled to a 10 dm3 system which produced antibody under conditions of Good Manufacturing Practice (GMP). A calculation of productivity between the scaled perfusion system and 260 dm3 batch cultures resulted in comparable antibody production, whereas the perfusion allowed a halving in medium utilisation. Reactivity assays conducted on the purified antibody from both batch and perfusion cultures showed no evidence of proteolysis or altered antibody activity in the final perfusion product. This study provides additional support for the use of homogeneous perfusion cultures in production of monoclonal antibodies under GMP conditions

A carbon flow model of the intertidal areas of the Severn estuary

SIGLELD:8253.977(STP--50). / BLDSC - British Library Document Supply CentreGBUnited Kingdo