Lining the walls of the intestine, cells help the body fight once morest certain infections. We already knew this, but some are even more effective than imagined: they are able to recognize bacteria already encountered and better deal with them.
‘Innate lymphoid cells 3’, widely present in the intestine, keep a form of memory of past infections, making them more effective in the event of reinfection, according to a study carried out in mice
In the intestine, cells play a lasting role once morest infections – Gallery
Lining the intestine, cells help the body fight once morest certain infections, but are also able to recognize bacteria already encountered, according to a study carried out by researchers attached to the Institut Pasteur and Inserm
‘Innate lymphoid cells 3’, widely present in the intestine, keep a form of memory of past infections, making them more effective in the event of reinfection, according to a study carried out in mice
‘Innate lymphoid cells 3’ (ILC3), widely present in the gut, retain a form of memory of past infections, making them more effective in the event of reinfection, according to a study in mice which is to be published Friday in the journal Science.
“Trained+ ILC3s emerge and remain present following a first encounter with a pathogen”, summarize the authors of this work, attached to the Institut Pasteur and Inserm.
This discovery makes it possible to better understand the functioning of the immune system, even if it should be kept in mind that it was carried out on animals and therefore cannot be mechanically applied to humans.
It is part of a series of recent works which have clarified the way in which the two major forms of immunity are articulated: innate and adaptive.
The second is the best known. It is through this, in particular through the creation of antibodies, that the body “learns” to recognize the bacteria and viruses that infect it over time, in order to target them specifically. It is used in particular as a basis for the functioning of vaccines.
“Innate” immunity, on the other hand, acts in a less targeted way. It allows the body to identify infectious agents without discrimination and immediately form a first barrier, while the adaptive response is organized.
But, for several years, a series of research has partly called into question this idea of a block and indiscriminate response. They show that certain players in the innate response, such as “natural killer cells”, are also likely to recognize a microbe that has already been encountered.
– A quickly reactivated immunity –
This is also the case for “ILC3” cells, according to the study published on Friday. Their role in innate defense was known for more than ten years, but not their gift of “memory”.
To highlight this, the researchers infected mice with a bacterium that acts in these animals in a similar way to Escherichia Coli, one of the main causes of infection in humans.
In infected animals, some of the ILC3 cells transformed into “trained” versions. Reinfected four months later with the same bacterium or with closely functioning cousins, these mice benefited from a better immune response.
This memory of ILC3 cells allows “to make them effective very quickly to immediately strengthen the barrier during a second infection”, summarized Nicolas Serafini, main author of the study, to AFP.
Assuming that these results can be confirmed in humans, they contribute to nuance a simplistic view of innate and adaptive immunity, in which the first would only prepare the ground for the second.
“We have the (false) impression that the innate response is something very simple like soldiers, and that we will have the + brain + of the adaptive response which will be really important to cure the infection” , explained to AFP James Di Santo, who supervised this study.
“What we are showing is that these + simple + cells are not that simple: they have this ability, like the adaptive system, to change their behavior”, he continues.
This work has as main interest to help to better describe the complex functioning of the immune system. On the other hand, it is far too early to say to what extent, with other studies going in the same direction, it announces concrete therapeutic advances.
But that does not preclude thinking regarding it theoretically and the researchers envisage that one day we can use these “trained” immune cells as a treatment once morest certain diseases, such as colon cancer.
“A fairly distant future would be to use these cells in cell therapy, if we are able to keep them alive for a very long time and reinject them,” suggests Mr. Serafini.
Lining the intestine, cells help the body fight once morest certain infections, but are also able to recognize bacteria already encountered, according to a study carried out by researchers attached to the Institut Pasteur and Inserm
‘Innate lymphoid 3’ cells, found widely in the gut, retain a form of memory of past infections, making them more effective in the event of reinfection, mouse study finds
AFP