The internationally-renowned scientific journal Immunity, from the Cell Press group, publishes online today, and will publish in its August 27 print issue, the results of a study conducted by a team of researchers led by Dr. André Veillette, Director of the Molecular Oncology research unit at the Institut de recherches cliniques de Montréal (IRCM). Their scientific breakthrough could have an impact on the treatment of multiple sclerosis and other autoimmune diseases, which affect tens of thousands of Canadians.
Dr. Veillette's team discovered the function of a protein located in T cells, which are immune cells known as lymphocytes that play a central role in the protection against viruses and other microbial agents. They also take part in the development of certain diseases, including diabetes and multiple sclerosis. The protein in question is the "phosphatase" PTP-PEST, an enzyme that removes phosphates from other proteins in the cell.
"By removing PTP-PEST from mouse T cells, we determined that this protein was required for repeated immune responses such as those occurring during vaccination," explains Dr. Dominique Davidson, a researcher in Dr. Veillette's laboratory and first author of the study. "More particularly, we showed that PTP-PEST controls the activity of Pyk2, a molecule that stimulates the ability of cells to interact with one another and move within the body."
The researchers showed that, through this mechanism, PTP-PEST stimulates the participation of T cells in an immune reaction. Once activated, T cells encourage other immune cells to join in an immune response, thereby explaining their pivotal role in this process. The team's results also show that the elimination of PTP-PEST in T cells can prevent certain autoimmune diseases, at least in mice. This suggests that suppressing the function of PTP-PEST through medication could be of value for the treatment of some human diseases.
"The removal of PTP-PEST can unfortunately prevent immunization and weaken the response to a vaccine," concludes Dr. Veillette. "Fortunately, it can also prevent overactive immune responses and could eventually help treat autoimmune diseases. It's like a double-edged sword."