LJI immunologist Mitchell Kronenberg, Ph.D., leads efforts to understand how healthy individuals contain infection by bacteria such S. pneumoniae. His team focuses on specialized populations of lymphocytes that make very rapid or innate-like immune responses against the pathogen. They found that when S. pneumoniae invades the lung, immune cells called invariant natural killer T (iNKT) cells mount an immediate and highly choreographed immune response that prevents the infection from progressing. Moreover, since iNKT cells in different patients appear to target S. pneumoniae in the same way (unlike other types of T cells) scientists may someday be able to reliably activate them to fight pneumonia in newly infected patients.
Kronenberg’s team is using mouse models and cutting-edge intravital microscopy to follow iNKT cell mobilization in living animals after S. pneumoniae infection. Their research charts how different subsets of iNKT cells emerge following infection, each secreting different chemical messenger (cytokine) signals at the “right” time. We now know that iNKT cell subsets can only neutralize lung infections if they are activated in a certain order in the right part of the airway. Researchers can build upon these findings to design potent pneumonia vaccines.