USE OF A NUCLEASE ENZYME IN THE PURIFICATION OF VAQTA(R), A HEPATITIS-A VACCINE

The development of the purification process for VAQTA(R), which result s in a highly purified inactivated hepatitis A vaccine, was driven by modifications in the cell-culture and harvest methods which permit hep atitis A virus propagation to support large-scale manufacture, The sta rting material for the purification was initially a concentrated cell pellet scraped from roller bottles, However, when the cell-culture met hod was scaled up to use high-surface-area Nunc cell factories or Cost ar cubes, the early steps in the process had to be modified to handle large volumes of dilute lysate, Membrane concentration was used at fir st, and a highly purified vaccine was prepared, but virus-poly(nucleic acid) complexes were formed, which reduced the yields in later proces sing steps, The introduction of a nuclease digestion immediately after harvest followed by capture chromatography an an anion-exchange colum n eliminated the formation af these complexes and resulted in more con sistent performance and higher yields of downstream operations.