Intestinal immune response

Lymphoid tissues such as lymph nodes both host immune cells and serve as filters or traps for foreign and infectious antigens. These tissues are fully formed at birth. One type of lymphoid tissue, ILFs, is instrumental in the immune response against intestinal pathogens. However, in contrast to other lymphoid tissues, ILFs are induced by environmental stimuli from microorganisms in the intestinal lumen. Indeed, the formation of these tissues is fully reversible.

In an effort to further understand the development of ILFs, McDonald et al discovered that intestinal microbes recruited clusters of dendritic cells, immune cells that present antigen to other cells, to ILFs. Moreover, depletion of these immune cells resulted in regression of ILFs. Indeed, ILF differentiation was dependent on the cell-migration molecule CXCL13, which is expressed by ILF dendritic cells. Taken together, these data indicate that dendritic cell recruitment plays a key role in ILF development and function, perhaps through the secretion of CXCL13.

Dr. Newberry's group "suggest[s] that like other cellular components of [solitary intestinal lymphoid tissues], [dendritic cells] perform dual functions by shaping their microenvironment and generating immune responses."