French researchers have developed a new vaccination process capable of being injected without a needle or adjuvant, but thanks to a laser. Hope for the most sensitive.
It may soon be over with the hassle of bites and controversy over aluminum in vaccines. In any case, this is what a study led by researchers from Inserm, CNRS and the University of Aix-Marseille can hope for. They managed to vaccinate mice against melanoma by administering a vaccine preparation without adjuvant, and all thanks to micropores formed in the skin via a laser. The results of this study were published in The Journal of Immunology.
Short-circuit the dendritic cell network
“Currently, a vaccine is injected with a needle which passes through the dermis and releases the vaccine solution into the hypodermis or into the muscle,” explains Bernard Malissen, co-author of this work. Researchers have developed a “targeted” vaccine and isolated an antigen found on the surface of melanoma cells. They then coupled it to a molecule called XCL1 which specifically binds to a receptor found on the surface of dendritic cells in the dermis (XCR1).
“We therefore bypass the dermis and its very dense network of XCR1 cells. These cells are extremely powerful sentinels of the immune system: they present antigens to immature T lymphocytes with a view to their differentiation into effector T lymphocytes, capable of eliminating the pathogen. We therefore wanted to specifically target these dendritic cells * in the dermis in order to stimulate the immune response, ”explains the author. This method thus avoids the need for adjuvants, conventionally used to stimulate the activation of the immune system.
As the XCR1 receptor is present from one species to another, and in particular in humans, “the transfer of this approach should be relatively simple to implement”, say the researchers. Furthermore, the method could be “used to vaccinate against different infectious agents”.
Boost the immune system
To achieve this needle-free vaccination, the research team used a laser commonly used in cosmetic surgery. They exposed the skin of mice (healthy or with melanoma) to this ray and then applied the vaccine solution locally. Results: the effect was rapid, since the vaccination stopped the progression of the tumor in the mice with melanoma and protected the healthy group in which tumor cells had been injected after the vaccination, against cancer.
“The vaccine was therefore effective in prevention and therapy, despite the absence of an adjuvant usually essential to stimulate the immune response in the event of vaccination against cancer. Perhaps the application of the laser causes a slight local inflammation which attracts immune cells (such as monocytes and granulocytes), potentiating the response generated by the vaccine. We are in the process of verifying that, ”concludes Bernard Malissen.
This new device would eventually make it possible to do without the very controversial adjuvants contained in current vaccines.
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