MDCK and Vero cells for influenza virus vaccine production: a one-to-one comparison up to lab-scale bioreactor cultivation

Abstract

Over the last decade, adherent MDCK (Madin Darby canine kidney) and Vero cells have attracted considerable attention for production of cell culture-derived influenza vaccines. While numerous publications deal with the design and the optimization of corresponding upstream processes, one-to-one comparisons of these cell lines under comparable cultivation conditions have largely been neglected. Therefore, a direct comparison of influenza virus production with adherent MDCK and Vero cells in T-flasks, roller bottles, and lab-scale bioreactors was performed in this study. First, virus seeds had to be adapted to Vero cells by multiple passages. Glycan analysis of the hemagglutinin (HA) protein showed that for influenza A/PR/8/34 H1N1, three passages were sufficient to achieve a stable new N-glycan fingerprint, higher yields, and a faster increase to maximum HA titers. Compared to MDCK cells, virus production in serum-free medium with Vero cells was highly sensitive to trypsin concentration. Virus stability at 37 degrees C for different virus strains showed differences depending on medium, virus strain, and cell line. After careful adjustment of corresponding parameters, comparable productivity was obtained with both host cell lines in small-scale cultivation systems. However, using these cultivation conditions in lab-scale bioreactors (stirred tank, wave bioreactor) resulted in lower productivities for Vero cells.

Traditional and New Influenza Vaccines

“…In addition, cell culture, unlike embryonated eggs, can be cryopreserved, reconstituted, and scaled up at any time. By process improvements such as cell adaptation and the use of bioreactors, vaccine strains can be successfully grown to high yields, although it is not clear if this is universally the case (72,73). To date, the continuous mammalian cell lines Vero (monkey kidney cells) and MDCK (canine kidney cells) and human-derived PER.C6 cells have been used successfully to prepare seasonal and prepandemic influenza vaccines (74,75).…”

Cell culture-based influenza vaccines: A necessary and indispensable investment for the future

“…92 Second, MDCK cells have been shown to be the most suitable for large-scale production of influenza virus. 89,93,94 Head-to-head comparison in laboratory scale bioreactors showed that MDCK cells yielded more virus than did Vero cells. 94 Third, influenza virus replicates more rapidly in MDCK cells compared to other cell lines, 95 and can be adapted to produce high titres in MDCK cells in as few as 3 to 10 passages, i.e., in 10-30 days, depending on the strain.…”

“…151,152 It was demonstrated that one of the reasons for this was that Vero cells contain an anti-tryptic activity, and that repeated addition of TPCK-treated trypsin could aid in multicycle replication and generation of high virus yields. 153 Even so, comparative studies have shown that whereas peak titres could be higher, 94 the growth of influenza A and B viruses may be slower in Vero cells compared to that in MDCK cells, 48,[93][94][95]101 and that extended passaging may be required to obtain high titer virus suitable for industrial scale production. 154,155 This may be disadvantageous in case of serious epidemics or pandemics, when vaccines need to be available in a short amount of time.…”

“…93 On the other hand, the ratio of genome copies to infectious unit or infectious unit to total virions have been found to be better with influenza A propagated in Vero cells than in MDCK cells. 94,95 The virus produced in Vero cells has also been shown to be more stable at least with A/H1N1, compared to MDCK-derived virus, especially when propagated in serum-free medium. 94 In addition, reverse genetics systems have also been developed so that high-yielding reassortant vaccine strains can be rapidly generated directly in Vero cells.…”

“…94,95 The virus produced in Vero cells has also been shown to be more stable at least with A/H1N1, compared to MDCK-derived virus, especially when propagated in serum-free medium. 94 In addition, reverse genetics systems have also been developed so that high-yielding reassortant vaccine strains can be rapidly generated directly in Vero cells. 49,156,157 A major issue with the use of MDCK cells for the production of influenza vaccines is tumorigenicity.…”