A breakthrough study into a prospective vaccine for multiple sclerosis (MS) has shown incredible results in mouse models, in which it delayed the onset of the disease and reduced the severity of symptoms whilst not displaying the immunosuppressive drawbacks of current treatment. The results, published in the journal Science by a team from BioNTech, follows the successful rollout of the SARS-CoV-2 vaccine and utilizes a similar principle to combat MS.
MS is a chronic, lifelong condition in which the immune system attacks nerve cells throughout the body. Symptoms range in severity, from mild and highly treatable, to severe, in which some people may require a wheelchair. As a result of nerve cell damage, patients with MS may experience partial blindness, muscle weakness, and coordination difficulty, although the onset and frequency of symptoms are highly varied.
Current treatments for MS involve targeting symptoms and alleviating them through drug treatments, or by the intense haemopoetic stem cell treatment that essentially destroys the immune system before regrowing cells that should not pose a threat to nerve cells. However, this is purely a preventative measure, so it cannot restore any lost muscle function, only works for some cases of MS, and is an incredibly difficult process.
Instead, BioNTech has developed a vaccine that uses mRNA to ‘teach’ the immune cells to tolerate the nerve cells instead of attacking them. Damage to neurons occurs after T cells, which regulate the immune response as well as releasing pro-inflammatory cytokines, recognize the protein that coats neurons, called myelin, as foreign.
To combat this, the vaccine presents disease-related antigens to a regulatory form of T cells, called Tregs. Tregs are involved in the suppression of the immune response, and teaching them to tolerate myelin-associated proteins should prevent auto active T cells from causing damage to the neurons.
Using tiny nanoparticles as a delivery vehicle targeting dendritic cells (an immune cell that activates other immune cells), the researchers administered the vaccine to mouse models with MS to see if symptoms improved. After administration, the therapy improved symptoms in mice and suppressed T effector cells that are thought to be responsible for MS disease onset. The effects were tissue-specific, so did not lead to a total downregulation of the immune system seen in other MS treatments.
The results provide another strong case for further research into mRNA vaccines and treatment. Targeted mRNA treatments hold promise in both large-scale treatments, being both cost-effective and mass-producible, and personalized treatments for serious conditions such as cancer. Such treatments still suffer from few delivery molecules that are targeted and safe, alongside some dosage issues, but it looks more and more likely the future of personalized medicine lies in mRNA.
