The time had come at the beginning of June: I received my first vaccination dose against Sars-CoV-2. Slight pain in my arm and tiredness the next day showed me that my immune system was probably reacting as intended. But what exactly happens in our body during such a vaccination? And above all: How can vaccines create immunity to a pathogen that often lasts for decades or even life, when most body cells are rather short-lived?
Marc Hellerstein from the University of California at Berkeley looks into such questions in the cover story of this issue starting on page 12. He developed new methodological approaches to find out how the memory of our immune system develops after being confronted with germs. Because this plays a central role in future long-term protection against the disease. Normally, however, the lymphocytes that are crucial for the immune system only live for a few days or weeks. After an infection or vaccination, do they possibly pass on information about the respective pathogen to successor cells before they die? However, it would also be conceivable that the cellular carriers of the immune memory are simply unusually persistent. In an experiment, the author was able to prove that some of the specifically reacting immune cells that formed after a yellow fever vaccination were actually still present in the body several years later. Such longevity is otherwise only known from nerve cells in the brain - by the way, the only other system in our body that also has a memory.
In addition to insights into the miracle of our body's defenses, Hellerstein's article outlines the success story of vaccinations - probably the greatest achievement in medicine and comparable in importance to technical developments such as electricity or the Internet. It's easy to forget what suffering used to be spread by things like polio, diphtheria or smallpox. According to estimates, around 300 million people died from the latter alone in the 20th century. Thanks to vaccines, these plagues have lost their terror.
Even in the current Covid-19 pandemic, vaccinations show us the way back to normality. Tests currently underway are intended to shed light on how permanently lymphocytes specialized in Sars-CoV-2 remain in our body. This could be the case for much longer than with the antibodies against the virus, which have so far mainly been studied. Then my vaccination could possibly protect me from an illness for many years.