BREATHE NEW LIFE INTO UNUSED VACCINES
by Simonas Bendžius
During the COVID-19 pandemic, pharmaceutical companies produced unprecedented quantities of vaccines. This helped save millions of lives, but on the other hand, many vaccines remained unused, expired, and had to be thrown away. To avoid such problems in the future, Lithuanian researchers at the Center for Physical Sciences and Technology (FTMC) are proposing an environmentally friendly solution as part of a project: perhaps expired vaccines could be repurposed for another purpose – the development of new biosensors?
A group of scientists demonstrated this possibility for the first time in the world in their article, which was recently published in the high-level international analytical chemistry journal Talanta.
The authors of the article are researchers from the FTMC Department of Nanotechnology: Dr Vincentas Mindaugas Mačiulis, Dr Asta Lučiūnaitė, Dr Mantvydas Usvaltas, Dr Silvija Juciūtė, and Prof. Dr Ieva Plikusienė, as well as Dr Almira Ramanavičienė, professor at the Faculty of Chemistry and Geosciences at Vilnius University.
The lead author of the study, Dr Mačiulis, talks about this work and its innovative goals.
At the very beginning of the article, you draw attention to a widespread problem that emerged during the height of the pandemic.
Yes, we have all heard that governments purchased large quantities of vaccines during the pandemic – but like all products, they have an expiration date. Some Western countries, such as France, donated some of their unused vaccines to other countries (for example, sending them to Algeria). The problem with such charity was that those vaccines were still close to their expiration date. In addition, vaccines require special storage conditions, refrigerators, etc. Where to put them? They had to be thrown away.
So we came up with an idea: could we give expired preparations a second life? It is worth mentioning that we focused our attention on the vaccines with virus-like particles (VLP). VLPs are protein structures that resemble real viruses but do not contain their genetic material (DNA or RNA). Therefore, they cannot cause infection, but the immune system recognizes them as a threat and begins to produce antibodies, thus forming immunity.
We used such COVID-19 vaccines in our study, but looking to the future, we can think more broadly: there are various types of VLP vaccines – for example, vaccines against human papillomavirus or hepatitis B are developed using the same technologies. So, could the method we are developing be adapted to prevent other diseases?
But for now, we have set ourselves two tasks: to use expired COVID-19 VLP vaccines and adapt them for use in biosensors that would help determine immunity to the coronavirus.
How did this “restoration” of old vaccines take place?
They were donated to us from the laboratory of Dr Aurelija Žvirblienė, a professor at the Life Sciences Center of Vilnius University (VU GMC). In addition to spike protein, the vaccine contains additional components – pharmaceutical substances that improve the stability of the drug, as well as adjuvants. The latter are molecules that stimulate the immune response so that the body recognizes the danger and begins to protect itself.
There are a lot of these additional substances in the vaccine. We needed to purify and obtain only spike proteins in order to get “clean,” “concentrated” vaccines. This work was done by my colleague Dr Asta Lučiūnaitė from VU GMC, who is also currently a research intern at the FTMC Department of Nanotechnology. She also conducted comparative studies to see whether the “cleaned” spike proteins react with antibodies. That was our initial task.
What happened next? Simply put, the spike proteins from the vaccines were “attached” (immobilized) to the gold surface using chemical bonds. This is how we prepared the surface, which we then used to detect antibodies. Now all that remained was to test how it works.
For this purpose, we used specially prepared blood serums containing different amounts of antibodies. They were tested using three different sensor surfaces. One contained our isolated spike proteins, another contained commercially available spike proteins from the virus strain that circulated at the beginning of the pandemic, and the third contained spike proteins from the Omicron variant of the coronavirus. We observed how each of them binds to antibodies in blood serum.
In other words, you observed whether these spikes with different mutations would recognize a person’s immunity to the coronavirus?
Yes, whether they were sufficiently protected or whether they should already be vaccinated.
As we described in the article, these first experiments were very successful. In this way, biosensors recognized antibodies using spike proteins obtained from outdated vaccines and provided reliable results. Compared to commercial “fresh” proteins, this interaction is not yet as accurate, but this is only the beginning. The overall result is encouraging – at this stage, the use of old vaccines is proving worthwhile.
As I mentioned, we are trying to be environmentally friendly so that vaccines no longer need to be discarded – and so that vaccine production itself becomes more sustainable. In addition, if we succeed in refining our method into biosensor technology, it will be a much cheaper way to detect specific antibodies. Every scientist working in this field will tell you that buying specially designed proteins is expensive – and in our case, laboratories could obtain expired vaccines much more cheaply.
What are your next steps?
Our research aimed to demonstrate that such a model system works. We want to continue this work, and it would also be interesting to conduct tests with other, non-COVID-19 vaccines to check immunity to other diseases. It is likely that the method would work in a very similar way, but we would need to make sure that it is possible to obtain the same results.
We also plan to improve the process of extracting spike proteins from old vaccines to improve their interaction with antibodies.
Source: Center for Physical Sciences and Technology
