Production and control of live oral poliovirus vaccine in WI-38 human diploid cells

Production of live poliomyelitis vaccine in human diploid cells WI-38 can be carried out successfully on a continuous basis. Starting at the 8th population doubling level it is possible to produce 128 ampoules, each containing 1 ml of cell suspension at the 16th level. Each of these cell seed ampoules will yield 85 bottles each with a surface area of 1400 sq. cm at the production level (P29) together with 85 Roux bottle cultures which act as controls. A further passage from the control cells yields a sufficient supply of cells for karyology, tumourigenicity and other tests. Virus yields of the Sabin strains are rather lower than those obtained in primary monkey kidney cells, but this is compensated for by the very much lower reject rate. Karyological characterisation is undoubtedly the most demanding of the testing procedures both in time and expertise. Other tests for contamination, other than bacteriological have yielded uniformly negative results. There is urgent need for standardization of the assay systems used in different laboratories and there is perhaps a case for the use of reference vaccine produced in homogeneic cells.