Analysis of Protease Activity in Live Antigen-presenting Cells Shows Regulation of the Phagosomal Proteolytic Contents During Dendritic Cell Activation

• DOI: 10.1084/jem.20020327
• Publication Date: 2002-09-30T17:03:17Z
• Authors: Ana-Maria Lennon-...; Arnold H. Bakker; René Maehr; Edda Fiebiger; Herman S. Overkleeft; Mario Rosemblatt; Hidde L. Ploegh; Cécile Lagaudrie...
• Keywords: Lipopolysaccharides; Cathepsin L; Cathepsin K; Down-Regulation; Cysteine Proteinase Inhibitors; Article; Cathepsin; Cathepsin B; Cell Line; Mice; 03 medical and health sciences; 0302 clinical medicine; Phagocytosis; Leucine; Active site-directed probe; Animals; Cells, Cultured; Mice, Knockout; Antigen Presentation; Binding Sites; Macrophages; Dendritic Cells; Cathepsins; Phagosomal maturation; Mice, Inbred C57BL; Cysteine Endopeptidases; Antigen processing

Here, we describe a new approach designed to monitor the proteolytic activity of maturing phagosomes in live antigen-presenting cells. We find that an ingested particle sequentially encounters distinct protease activities during phagosomal maturation. Incorporation active proteases into phagosome macrophage cell line J774 indicates maturation involves progressive fusion with early and late endocytic compartments. In contrast, biogenesis bone marrow–derived dendritic cells (DCs) macrophages preferentially compartments enriched cathepsin S. Kinetics is faster than DCs. Furthermore, delivery significantly reduced after activation DCs lipopolysaccharide. This observation agreement notion prevent premature destruction antigenic determinants optimize T activation. Phagosomal therefore tightly regulated process varies according type differentiation stage phagocyte.