Adapting Influenza Viruses to Vero Cells via Sequential Passage
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Solution Overview
Problem
Current methods for producing influenza vaccines using embryonated chicken eggs are time-consuming, costly, and prone to cross-infection, with ECE-derived influenza viruses not growing to high titer in Vero cells, necessitating a method for fast adaptation of these viruses to Vero cells for efficient vaccine production.
Innovation Solution
A method involving infecting Vero cells with an influenza virus at a first infectious dose, cultivating in a spinner flask, harvesting, and repeating the process with increasing infectious doses to adapt the virus, achieving a Vero cell-adapted influenza virus in 5-10 passages, and using a composition including polyriboinosinic acid-polyribocytidylic acid (PIC), antibiotics, and positive ions for large-scale production and nasal-spray vaccine development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If embryonated chicken eggs are used for influenza vaccine production, then vaccine production can be performed using traditional methods, but the process becomes time-consuming and costly with cross-infection risks
Solution Approach 1:
The patent changes the host cell parameter from embryonated chicken eggs to Vero cells, and modifies the infection conditions by using sequential passages with increasing MOI. This parameter change enables the virus to adapt to the new host system, achieving faster growth kinetics and higher titers in Vero cells compared to traditional egg-based methods, thereby reducing production time while maintaining reliability
Solution Approach 2:
The patent applies preliminary action by performing serial passages of the influenza virus in Vero cells before actual vaccine production. The virus is pre-adapted to the Vero cell system through multiple passages with progressively increasing MOI, ensuring that the virus stock is optimized for high-yield production in the cell culture system before scaling up to manufacturing, thus reducing the time required during actual production
2Productivity
If sequential passages with increasing MOI are used to adapt virus to Vero cells, then adaptation speed increases to 5-10 passages, but the process complexity increases
Solution Approach 1:
The patent segments the virus adaptation process into multiple sequential passages, each with a specific MOI range. This segmentation allows systematic progression from low to high MOI, enabling the virus to gradually adapt to Vero cells without overwhelming the cells in early passages. The segmented approach achieves high productivity through controlled incremental adaptation rather than a single complex step
Solution Approach 2:
The patent applies dynamics by making the MOI a dynamic parameter that changes across passages rather than remaining constant. The MOI is progressively increased from 0.001-0.01 in early passages to 0.1-1.0 in later passages, creating a dynamic adaptation process that optimizes both cell survival and viral replication at each stage, ultimately achieving high virus titers in a manageable number of passages
3Ease of manufacture
If ECE-derived influenza viruses are used directly in Vero cells, then vaccine production can begin, but the viruses do not grow to high titer
Solution Approach 1:
The patent ensures continuity of useful action by maintaining viral replication throughout sequential passages in Vero cells. Rather than interrupting the adaptation process, the virus is continuously propagated through multiple passages with increasing MOI, allowing cumulative adaptation effects to build up. This continuous propagation ensures the virus develops optimal growth characteristics for high-titer production in Vero cells while maintaining ease of manufacture through a standardized protocol
Data Source
AI summary
A method for adapting an influenza virus to Vero cells is provided. The method comprises infecting Vero cells with the influenza virus, cultivating the infected Vero cells, harvesting influenza viruses of each passage, wherein infectious dose of the influenza viruses of one passage is greater than or equal to infectious dose of the influenza viruses of a previous passage. The present disclosure also relates to a composition. Said composition comprises polyriboinosinic acid-polyribocytidylic acid, at least one antibiotic or polyamide compound, at least one positive ion, influenza viruses and/or influenza antigens, wherein said influenza viruses and/or influenza antigens are acquired from Vero cell adapted influenza viruses.