Preparing for an influenza pandemic: A discussion with Professor Amine Kamen from the Viral Vectors and Vaccines Bioprocessing Group

Figure 1: Professor Amine Kamen, Canada Research Chair in Bioprocessing of Viral Vaccines, and the Viral Vectors and Vaccines Bioprocessing in their lab in the Department of Bioengineering at McGill University

Our capacity to respond to an influenza pandemic threat is presently limited by the methods used to manufacture vaccines, as reported in the last WHO (World Health Organization) Informal Consultation report 2015 [1]. The egg-based method, which consists of growing influenza viruses in eggs to produce a vaccine, is a system that has been used for more than 60 years and that is still presently used to produce most licensed influenza vaccines. However, this method requires 6 months to produce the candidate vaccine virus. Therefore, the need to develop new vaccine manufacturing technologies is crucial. This is exactly what Professor Amine Kamen, Canada Research Chair in Bioprocessing of Viral Vaccines, and the Viral Vectors and Vaccines Bioprocessing Group are doing in their lab in the Department of Bioengineering at McGill University (figure 1). I had a chance to sit down with Professor Kamen and discuss his latest paper Accelerated mass production of influenza virus seed stocks in HEK-293 suspension cell cultures by reverse genetics” [2].

Context

To start off the interview, I asked Professor Amine Kamen how he came to hold the position of Canada Research Chair in Bioprocessing of Viral Vaccines.

Professor Amine Kamen is a chemical engineer that turned to bioengineering more than 30 years ago. He tells me that, at that time, bioengineering was supposed to solve all the problems, so he naively passed from mining engineering to bioengineering. He became aware of the challenges in scaling up insect cells, used as an expression system for recombinant proteins and several complex structures, for large production in bioreactors through his collaboration with École Polytechnique de Montréal. Professor Kamen explained that, at that time, the challenges were engineering challenges like the stress imposed to the cells when you scale them up. He was later hired at the National Research Counsel of Canada where he pursued work on cell culture engineering with a focus on gene delivery. That is how he ended up working actively with the HK293 human cell line 27 years ago. Professor Kamen pointed out that he was the one who put forward cell culture at the NRC. Five years ago, he moved his work to McGill University as a senior researcher, where he gained access the Canada Research Chair in Bioprocessing of Viral Vaccines position. Interestingly, what drove him to go to McGill was that the activity at the university was limited by the number of qualified people in the cell area.

Taking advantage of Professor Kamen’s expertise, I wanted to know what were, according to him, the biggest challenges right now in developing a vaccine that could effectively respond to a global pandemic situation?

Professor Amine Kamen started off by emphasizing that this was a very important question: “Vaccines have always been very particular in the sense that it’s a public health issue. It is not an area where any industry would embark thinking they will make a lot of money. In fact, people that worked on the Ebola vaccine knew they were not going to make any money out of it. The requirement of time to develop a vaccine is a critical challenge. For example, the HPV vaccine from the primary discovery to the commercialization took 20 years. The timeline is so long there is hesitation for anyone to embark in the sector.” But despite this, there is, according to Professor Kamen, a lot of nontraditional support. Vaccine research is supported by nonprofit organization because of its importance. It is not a lack of money; it is a lack of resources.

“Vaccines are also more difficult than anything else because of the safety aspect to it. You are vaccinating healthy people. You cannot come forward with something that just addresses the short term, and this puts a huge pressure on the research. There is a consensus now that we need to integrate technical advancements but, at the same time, there is hesitation as the field is very conservative because of the safety aspect. So, in conclusion, it is many interacting factors that make the field challenging.”

Figure 2: HEK293 cell line used in in Professor Kamen’s research for large-scale transfection in suspension culture

Research

To get into the heart of the subject, I began discussing with Professor Kamen about the past research he used to produce his most recent results.

Firstly, Professor Amine Kamen explained that his other publications made the demonstration that we can use the HK293 human cell line as a manufacturing system for the influenza vaccine, which was the starting point (figure 2). This novelty was not easy to introduce in the vaccine manufacturing community due to the conservatism of the field.

When it comes to present research in vaccine manufacturing, Professor Kamen explained that the goal is not to produce a technology that will produce the seasonal influenza vaccine, which is done with the egg-based method which is fine. The demonstration has been clearly made that, in a pandemic time, it is impossible for the egg-based method to meet the need that would be required for vaccination of the population affected.  Therefore, the US government put forward 2 billion dollars to develop new technologies as an alternative to egg-base. From this big funding, two new methods to produce vaccines emerged: the method using MDCK cells in suspension and the recombinant vaccines.

I went on to discuss in more detail the research currently being done in Professor Kamen’s lab.

He told me that they were actively trying to propose a method that will accelerate and intensify vaccine manufacturing. The goal is to turn a months-long production process (egg-based manufacturing takes 6 months like I mentioned earlier) into something that would take a matter of weeks.

In relation to his most recent research, Professor Kamen says “We were able to make the demonstration. There is certainly the need to demonstrate the robustness. But this work is still ongoing.” He also summarizes the goals of his ongoing research: “The key elements are intensifying while keeping the quality and the cost effectiveness, but also shortening the timeline and that is the acceleration aspect.” The idea behind Professor Kamen’s method is to use the HEK-293 suspension cell line as a platform and take advantage of the recombinant technology (figure 3), therefore using the two new technologies that were developed from government funding and putting these together for a more efficient production of vaccines. The recombinant technology makes it so the production of the new influenza vaccine would only require the HA and NA sequences, while the same platform cells would be used for the manufacturing. Professor Amine Kamen explained that, in fact, the recombinant aspect provides acceleration because you just get the indication of the dominant strain sequences identified as a potential pandemic by the WHO, which can then start vaccine production immediately.

Figure 3: Schematic representation of how the influenza virus can be generated by reverse genetics. First, suspension HEK-293 cells are cultured in a bioreactor until the cell reach a certain density. Then, cells are transfected with plasmids containing the genetic material for the influenza virus (the plasmid is introduced in the cell for the cell to produce the virus). The viral particles produced (P0-BR) are harvested after 48 hours. Then the virus is amplified by infecting a new culture of suspension HEK-293 cells and harvesting the virus (P1-BR) after 72 to 96 hours.

The advancements put forward by Professor Amine Kamen’s most recent research are very promising. I asked Professor Kamen why it had not been done before and what were the biggest challenges in his present research?

Professor Kamen points out a limitation that is not obvious in the case of reverse genetics with influenzas that is that it has been patented. Therefore, there is resistance from the others to use it in their research. This is, in fact, an aspect that limits the use of reverse genetics. Also, not many people are qualified to used recombinant methods. Professor Amine Kamen also told me that, unfortunately, it is mostly the fact the field is extremely conservative; when something has been proven, you don’t want to change it. When it comes to vaccine manufacturing, regulatory agencies need to come within the facility at multiple stage to release a lot of candidate vaccine virus, which is not something common for biologists. Therefore, new methods for vaccine manufacturing take longer to develop than any other product.

Next and on a more technical note, I discussed with Professor Kamen that in his paper, he mentions that reverse genetics at large-scale did not induce variation of the viral population, but these results were obtained after only one amplification step. I asked him what were the expected effects on the accuracy of reverse genetics when multiple amplification steps are done?

Professor Amine Kamen told me that this was a question of looking at the robustness of the method. He explained that after getting a virus from reverse genetics, the nest steps are to infect a cell and replicate the virus. But it turned out that you don’t need to replicate multiple times. The replication is so efficient that the you only need very minimal quantity of virus to have a productive culture. Therefore, only two or three replication steps are needed for manufacturing the vaccine. There is still a need for sequencing and demonstrating there is not a significant evolution over passages. “It is something to demonstrate but I am confident that this will not be the case” told me Professor Kamen. There is also added value to the efficiency of the method because you can rapidly obtain the virus with the transient transfection and show it matches the dominant strain. In the case of the egg-based method, it takes three months to get the virus and with the evolution of the dominant strain, you might have a mismatch. In fact, Professor Kamen explained there is race from the announcement of the dominant strain by the WHO between the manufacturing of the vaccine and mutation of the dominant influenza strain. If you can shorten the production time, it is less likely there will mismatch between the virus and the vaccine.

Future work

To conclude our discussion, I asked Professor Kamen what is the next step in your research in an alternative production method for vaccine manufacture?

Professor Amine Kamen tells me that work is currently ongoing in his lab. There is funding to continue the project. Up to now, it is one step of vaccine manufacturing that his research has focused on which was making the seed stock. But there are many other steps in producing a vaccine, like large scale production, inactivating and purifying the vaccine. Research regarding all these steps is currently taking place. Professor Kamen reminded me that the idea for the following research was still to make vaccine production as simple and cost effective as possible by intensification and acceleration. “If you simplify it, more people will adopt it.” He also explained that the idea is this should be a technology that is not only available to the experts to be put forward in situations of pandemics. The reality is that, presently, most labs are not qualified to use this method. Therefore, another step for Professor Amine Kamen would be to get people to be qualified to use this method instead of the egg-based.

Finally, Professor Amine Kamen left me with his expert words of advice: “A pandemic is not a question of if, but when. Therefore, we need to prepare in times of peace!”

References

[1]          WHO Global Influenza Programme. Report of a WHO Informal Consultation held in Geneva, Switzerland Influenza Vaccine Response during the Start of a Pandemic Influenza Vaccine Response during the Start of a Pandemic; 2015.

[2]          E. Milián, T. Julien, R. Biaggio, A. Venereo-Sanchez, J. Montes, A. P. Manceur, S. Ansorge, E. Petiot, M. Rosa-Calatrava and A. Kamen, “Accelerated mass production of influenza virus seed stocks in HEK-293 suspension cell cultures by reverse genetics”, Vaccine, vol. 35, no 26, p.3426-3430, Jun 2017.

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