Characterizing follicular dendritic cells: A progress report.

In 1965, Mitchell and Abbot (Mitchell, J. and Abbot A, Nature 1965. 30: 500-502) discovered peculiar cells with filiform processes, which were capable of capturing and retaining antigens within secondary lymphoid organs. Yet half a century since the first description of follicular dendritic cells (FDC), their function and their histogenesis remain largely mysterious. FDC are thought to help with organization of the lymphoid follicles, to facilitate the germinal center reaction by presenting antigen to B cells, and to legislate the engulfment of apoptotic bodies, but it has proved difficult to stringently verify any of these functions. One reason for such slow progress is a dearth of markers specific to FDC and their precursors, which limits our ability to isolate, target, and follow FDC. Here we review the current state of FDC science with specific reference to a study in this issue of the European Journal of Immunology and its efforts in discovering new FDC markers.