The focus of this WP will be to characterize newly emerging subsets of lymphocytes, characterized by the secretion of selected panels of cytokines. In particular, Th2 cells, often considered as a homogenous cell population, have recently found to comprise cells displaying distinct functional characteristics.
Some Th2 population bear some resemblance with follicular helper T cells (TFH), a subset of cells known to induce humoral responses characterized by the presence of long-lived plasma cells secreting high affinity antibodies. Whether TFH represent a distinct T cell subset or a transient differentiation state of cells otherwise committed to become classical Th2 (or even Th1, to be explored) is still a matter of debate and will be examined. Similarly, cells producing IL-9 (originally a bona fide Th2 cytokine) have been recognized (in particular within our consortium) as a separate subset of cells whose function will be explored within the frame of this project.
Finally, groups of cytokines previously thought to be regulated in a concerted fashion (IL-17 and IL-22 in particular) have also been shown to be produced by multiple cellular sources that we wish to further characterize. Relevant in vivo models will be developed to better understand the molecular details governing the expression of these cytokines and their physiological role.