Isolation of active peptides from plant hydrolysates that promote Vero cells growth in stirred cultures

Background Vero cells are adherent cell lines commonly used for the production of viral vaccines. We had developed an animal component free medium that allows an optimal growth of this cell line in stirred bioreactor [1,2]. We had also showed that Vero cells grown in this medium (called IPT-AFM) sustained rabies virus replication, and resulted in an overall yield comparable to the level obtained in serum-supplemented medium. IPT-AF medium contains plant hydrolysates, namely soy (Hypep 1510) and wheat gluten hydrolysates (Hypeps 4601 and 4605). These peptones were shown to promote cell attachment and growth. However, although these components are of non-animal origin, their use in vaccine production process has several drawbacks, mainly due variability between lots. The aim of this work is to identify active peptides from these hydrolysates that show a positive effect on cell adhesion, attachment and growth. For this purpose, the hydrolysates were fractionated using chromatography and precipitation techniques. The effect of the isolated fractions on Vero cells growth were tested in 24 and 6-well cell culture plates using experimental design approach. Fractions that sustain cell growth, were further tested in stirred culture on Cytodex1 microcarriers, to confirm their positive effect on Vero cells growth.