The human body is equipped with a variety of mechanisms to combat invading pathogens. One such mechanism is the formation of memory cells which help provide long-lasting immunity against future infections. Recently, tissue-resident memory cells have emerged as an important player in this battle against pathogens. A new study on mice has highlighted the critical role tissue-resident memory cells play in providing immunity against Salmonella. Understanding the functioning of these cells could potentially lead to the development of better strategies to prevent and treat infections caused by this bacterial pathogen.
Salmonella infections are responsible for an estimated one million deaths globally each year, and improved vaccines for both typhoid fever and non-typhoidal Salmonella disease are urgently needed. Researchers at the UC Davis School of Veterinary Medicine have published new work showing how memory T cells can be successfully recruited into the liver of a mouse model of Salmonella, an important finding for vaccines that aim to induce a powerful immune response.
The study, which was published in Proceedings of the National Academy of Sciences on April 11th, demonstrates how tissue-resident memory cells are key to immunity to Salmonella in mice. When the immune system detects a pathogen, an immune response is mounted, including CD4 T-cells which support other responses such as antibody production by B-cells. Memory cells then remain waiting to respond if the same threat returns.
By adapting an approach used by previous researchers studying malaria, the team successfully transferred CD4 T-cells specific for salmonella into mice that had never been infected and studied which factors would cause those T-cells to become resident memory cells in the liver. They discovered that inflammatory molecules, particularly interleukin-1 and -2, spurred the formation of Salmonella-specific tissue-resident memory cells. The researchers believe that this provides a rapid-response force to act quickly against Salmonella infection.
The results will help researchers in designing new vaccines for Salmonella, commented senior author Professor Stephen McSorley, Department of Anatomy, Physiology and Cell Biology, explaining, “A successful vaccine would need to promote conditions to form these cells, without causing liver inflammation.”
The study could be an important step forward in curbing Salmonella infections, which remain a major source of concern worldwide.
In conclusion, the presence of tissue-resident memory cells plays a crucial role in protecting against Salmonella infection in mice. This study highlights the importance of understanding the complex mechanisms of host-pathogen interactions, and the potential for manipulating the immune system to enhance protection against infectious diseases. Further research in this area may lead to the development of new therapeutic strategies to combat Salmonella and other bacterial infections in humans, offering hope for a healthier future.
