After a vaccination, antibodies not only patrol the blood, but the body also builds up a protective immune memory in organs such as the kidneys or lungs.
As the university hospital reported Wednesday, researchers at Berlin’s Charité University Hospital have proved this using mRNA vaccines against the coronavirus. According to the study, the immune memory cells in the organs are even more numerous than in the blood and have enhanced antiviral defence functions.
Enhanced antiviral defence function
The researchers assume that similar processes also occur after other vaccinations. There were already corresponding indications from experiments in animal models. To demonstrate this in humans, tissue from many patients with known and comparable immunization histories who have preferably never been infected by the pathogen is required. The coronavirus pandemic has now made this possible.
For the study, the researchers examined tissue from different organs, such as that produced during tumour surgery. The samples came from 61 people who had been vaccinated against the coronavirus two to three times with an mRNA vaccine a few months earlier, independently of the operation, but most of whom had not yet undergone the infection.
CD4-positive T-helper cells detected
Using particular approaches, the researchers were able to identify CD4-positive T helper cells in numerous organs that were directed toward SARS-CoV-2. These immune memory cells ensure that other immune cells produce appropriate antibodies against the pathogen as soon as it is detected in the body. They are also thought to help fight the virus directly.
The scientists found immune memory cells not only in the spleen and bone marrow, where immune cells mature or are produced by default but also in the liver, kidneys and lungs. They said this confirms that after vaccination, the body builds up a stable immune memory for months, even in tissues far from the injection site.
Moreover, the number of protective immune cells in the organs was similar regardless of the age of the vaccinated person. In contrast, fewer immune memory cells circulate in the blood of the elderly than in younger patients. The work appeared in the Journal of Clinical Investigation.
- source: k.a/picture: pixabay.com
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