title: Endocytic routes of exogenous antigen in murine dendritic cells and macrophages.
abstract: OBJECTIVE
  To compare the endocytic routes of exogenous antigen between murine dendritic cells (DCs) and macrophages (M phi s).
  
  
  METHODS
  Murine bone marrow-derived DCs and peritoneal M phi s were pulsed with horseradish peroxidase (HRP)-5 nm colloidal gold for 10 minutes, then grouped and chased for 0-120 minutes in culture medium. Intracellular distribution of 5 nm colloidal gold was explored by means of the cellular enzymatic-chemistry of acid phosphatase and MHC II immuno-cytochemistry under electron microscope.
  
  
  RESULTS
  After 10 minutes of pulse with HRP-5 nm colloidal gold and 30 minutes of chase, most HRP-5 nm gold particles internalized by DCs entered into MHC class II compartments (M II Cs), and a small portion entered into acid phosphatase-positive lysosomes. In contrast to DCs, most M phi s lysosomes were accessed by HRP-5 nm gold particles, and a small portion of HRP-5 nm gold particles entered into M II Cs. After 60 minutes of chase, 5 nm gold particles could hardly be seen within M phi s, whereas most 5 nm gold particles were still retained in DCs.
  
  
  CONCLUSIONS
  The endocytic route of exogenous antigen in DCs seems to be different from that in M phi s. Antigens taken by M phi s mainly enter into lysosomes within 30 minutes. In the case of DCs, most internalized antigens enter into M II Cs, which may be related to their unique antigen-presenting function. In addition, M phi s seem to have more powerful capacity to scavenge exogenous antigen than DCs.
authors.affiliation: Department of Cell Biology, Second Military Medical University, Shanghai 200433, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Xie
authors.forename: X
authors.initials: X
authors.lastname: Cao
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Ye
authors.forename: B
authors.initials: B
authors.lastname: Yu
authors.forename: Z
authors.initials: Z
authors.lastname: Zheng
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D017951:Antigen Presentation; D003713:Dendritic Cells / Q000378:metabolism*; D004705:Endocytosis; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D016253:Microscopy, Immunoelectron
chemical_list: D000135:Acid Phosphatase