Process Optimization for Influenza NA-VLP Vaccine Development using Baculovirus/Insect Cell System

Recombinant protein based virus- like particles ( VLPs) vaccine produced in insect cell using baculovirus expression vector was one of the methods developed to overcome the limitations of influenza vaccine eggbased production. This study focused on bioprocess development of influenza NA-VLP vaccine from the baculovirus/insect cells system. The NA-VLP production and purification processes were optimized. Infection of recombinant NA baculovirus at MOI 1 into 1x106 cells/ml insect cells in active growing phase for 4 days resulted in the highest NA-VLP level. The NA-VLP could be mostly purified by two conventional methods i.e. ultrafiltration and size exclusion chromatography. Firstly, NA- VLP was concentrated and purified from a major contaminant protein, albumin, by the cross flow ultrafiltration using 500 kDa membrane. More than 97% of albumin removal was achieved in this process. The largest NA-VLP could be obtained after size exclusion chromatography. Albumin was also further removed from this step. It was found that recombinant NA baculovirus could not be efficiently removed by these two steps purification process. One more simple purification by anion exchange ( AEX) chromatography using flow- through mode is recommended.