Prolonging Antigen Presentation

Science's STKE  15 Mar 2005:
Vol. 2005, Issue 275, pp. tw101
DOI: 10.1126/stke.2752005tw101

It has been assumed that antigen-presenting cells must have exceptionally well developed capacities for proteolysis because they must degrade protein antigens to perform their function. However, Delamarre et al. now find that the most efficient of the antigen-presenting cells (dendritic cells and B cells) harbor exceptionally low concentrations of lysosomal proteases when these levels are compared with those of macrophages. Dendritic cells also contain endogenous protease inhibitors that further attenuate their proteolytic potential. Remarkably, the levels of other lysosomal hydrolases in dendritic cells are similar to those found in macrophages. Thus, whereas macrophages rapidly degrade the antigens they encounter, dendritic cells may protect the very same antigens, facilitating their dissemination to and survival in secondary lymphoid organs.

L. Delamarre, M. Pack, H. Chang, I. Mellman, E. S. Trombetta, Differential lysosomal proteolysis in antigen-presenting cells determines antigen fate. Science 307, 1630-1634 (2005). [Abstract] [Full Text]