Researchers at La Jolla Institute
for Allergy & Immunology (LIAI) have identified two molecules (TL and CD8aa) that cooperate to trigger immune cells to develop into long-lived memory cells to fight recurring infections. This finding may have important implications for the future development of longer lasting and more potent vaccines for viruses such as HIV and West Nile.
In a paper (CD8aa Mediated Survival and Differentiation of CD8 Memory T Cell Precursors), published today in the scientific journal Science, Hilde Cheroutre, Ph.D., and a team of scientists have found that the TL and CD8aa molecules can not only drive activated immune cells to develop into long-lived memory cells, but can also identify which of the immune cells become memory cells.
During an infection, immune cells are activated and fight the infectious assault. These activated immune cells are programmed to undergo death immediately at the end of such a defense response. However, a few of the activated cells survive as memory cells. These memory cells are important since they can persist for the life of the individual and will act rapidly upon encountering the same infection later in life to provide immediate protection. This is why people do not get sick twice from chickenpox and other infections.
"These two molecules (TL and CD8(alpha)(alpha)) are induced during this defensive response and provide survival signals to the responding immune cells, which allow them to develop into long-lived memory cells," Cheroutre said. "With more of these memory cells, the body can better fight the infection should it arise again. This has major implications for the development of vaccines which will protect people longer and more effectively against disease."