Innovations in cell culture-based influenza vaccine manufacturing - from static cultures to high cell density cultivations

Abstract

Influenza remains a serious global health concern, causing significant morbidity and mortality each year. Vaccination is crucial to mitigate its impact, but requires rapid and efficient manufacturing strategies to handle timing and supply. Traditionally relying on egg-based production, the field has witnessed a paradigm shift toward cell culture-based methods offering enhanced flexibility, scalability, and process safety. This review provides a concise overview of available cell substrates and technological advancements. We summarize crucial steps toward process intensification - from roller bottle production to dynamic cultures on carriers and from suspension cultures in batch mode to high cell density perfusion using various cell retention devices. Moreover, we compare single-use and conventional systems and address challenges including defective interfering particles. Taken together, we describe the current state-of-the-art in cell culture-based influenza virus production to sustainably meet vaccine demands, guarantee a timely supply, and keep up with the challenges of seasonal epidemics and global pandemics.

Keywords: Influenza virus production; cell culture-based viral vaccine manufacturing; high cell density; perfusion cultivations; process development; process intensification.

Figure 1.

Technological advancements in cell culture-based influenza virus production processes using MDCK cells. Traditional egg-based processes were available since the 1940s (red arrow). Starting from the initial isolation of MDCK cells from the kidney of a healthy cocker spaniel by Madin and Darby in 1958, various options for cell culture-based production were established. Advances in medium development and the adaptation of MDCK cells to suspension growth have opened the possibility for establishment of more efficient and intensified processes. For perfusion processes relying on suspension cell lines, a bioreactor system is coupled to a cell retention device that can either be membrane-based or an inclined settler (gravity) or acoustic filter. Since the turn of the millennium, MDCK cell-based processes were licensed for the production of human influenza vaccines (blue arrows). BR: bioreactor; CSTR: continuous stirred tank reactor.

Figure 2.

Comparison of available cultivation systems for influenza vaccine manufacturing in adherent or suspension cells. STR: stirred-tank bioreactor; OSB: orbitally shaken bioreactor (single use); Wave bioreactor (single-use); semi-perfusion in shake flask; ATF: alternating tangential flow filtration; TFF: tangential flow filtration; TFDF: tangential flow depth filtration; AS: acoustic settler; IS: inclined settler; HFBR: hollow-fiber bioreactor; semi-continuous: two-stage semi-continuous shake flask cultivation system; CSTR: two-stage continuous stirred-tank bioreactor cultivation system.