| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Institute of Pathology, Case Western Reserve University, Cleveland, OH, 44106
Phagosomes contain class II MHC (MHC-II) and form peptide:MHC-II complexes, but the source of phagosomal MHC-II molecules is uncertain. Phagosomes may acquire nascent MHC-II or preexisting, recycling MHC-II that may be internalized from the plasma membrane. Brefeldin A (BFA) was used to deplete nascent MHC-II in murine macrophages to determine the relative contributions of nascent and recycling MHC-II molecules to phagocytic Ag processing. In addition, biotinylation of cell-surface proteins was used to assess the transport of MHC-II from the cell surface to phagosomes. BFA inhibited macrophage processing of latex bead-conjugated Ag for presentation to T cells, suggesting that nascent MHC-II molecules are important in phagocytic Ag processing. Furthermore, detection of specific peptide:MHC-II complexes in isolated phagosomes confirmed that BFA decreased formation of peptide:MHC-II complexes within phagosomes. Both flow organellometry and Western blot analysis of purified phagosomes showed that about two-thirds of phagosomal MHC-II was nascent (depleted by 3 h prior treatment with BFA) and primarily derived from intracellular sites. About one-third of phagosomal MHC-II was preexisting and primarily derived from the plasma membrane. BFA had little effect on phagosomal H2-DM or the degradation of bead-associated Ag. Thus, inhibition of phagocytic Ag processing by BFA correlated with depletion of nascent MHC-II in phagosomes and occurred despite the persistent delivery of plasma membrane-derived recycling MHC-II molecules and other Ag-processing components to phagosomes. These observations suggest that phagosomal Ag processing depends primarily on nascent MHC-II molecules delivered from intracellular sites, e.g., endocytic compartments.
This article has been cited by other articles:
|
|
 |
|
  E. W. Eng, A. Bettio, J. Ibrahim, and R. E. Harrison MTOC Reorientation Occurs during Fc{gamma}R-mediated Phagocytosis in Macrophages Mol. Biol. Cell, July 1, 2007; 18(7): 2389 - 2399. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Touret, P. Paroutis, and S. Grinstein The nature of the phagosomal membrane: endoplasmic reticulum versus plasmalemma J. Leukoc. Biol., June 1, 2005; 77(6): 878 - 885. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Ramachandra, J. L. Smialek, S. S. Shank, M. Convery, W. H. Boom, and C. V. Harding Phagosomal Processing of Mycobacterium tuberculosis Antigen 85B Is Modulated Independently of Mycobacterial Viability and Phagosome Maturation Infect. Immun., February 1, 2005; 73(2): 1097 - 1105. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Hmama, K. Sendide, A. Talal, R. Garcia, K. Dobos, and N. E. Reiner Quantitative analysis of phagolysosome fusion in intact cells: inhibition by mycobacterial lipoarabinomannan and rescue by an 1{alpha},25-dihydroxyvitamin D3-phosphoinositide 3-kinase pathway J. Cell Sci., April 15, 2004; 117(10): 2131 - 2140. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. R. Moller and E. S. Chen Genetic Basis of Remitting Sarcoidosis: Triumph of the Trimolecular Complex? Am. J. Respir. Cell Mol. Biol., October 1, 2002; 27(4): 391 - 395. [Full Text] [PDF]
|
|
|
|
 |
|
 L. Ramachandra, E. Noss, W. H. Boom, and C. V. Harding Processing of Mycobacterium tuberculosis Antigen 85B Involves Intraphagosomal Formation of Peptide-Major Histocompatibility Complex II Complexes and Is Inhibited by Live Bacilli that Decrease Phagosome Maturation J. Exp. Med., November 12, 2001; 194(10): 1421 - 1432. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
