Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1993-11-9
pubmed:abstractText
Exogenous protein Ag are processed within endocytic compartments to produce peptides that bind to class II MHC (MHC-II) molecules for presentation to T cells. We have now identified a subcellular compartment in which immunogenic peptides bind to MHC-II as a subset of high density lysosomes. Immunoelectron microscopy of whole cells and dense Percoll gradient subcellular fractions showed early tubulovesicular lysosomes with high levels of MHC-II. Typical mature lysosomes contained less MHC-II. Pulse-chase biosynthetic labeling of macrophages followed by immunoprecipitation of MHC-II from dense lysosomal fractions showed that MHC-II molecules targeted efficiently to lysosomes after biosynthesis. Moreover, lysosomal MHC-II molecules were rapidly loaded with immunogenic peptide (as detected by T cells) soon after exposure of macrophages to Ag and before similar expression of peptide-MHC-II complexes on the plasma membrane; this loading was blocked at 18 degrees C. We propose that nascent MHC-II molecules target to early tubulovesicular lysosomes and bind immunogenic peptides therein; the resulting peptide-MHC-II complexes are then transported to the plasma membrane.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
151
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3988-98
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Immunogenic peptides bind to class II MHC molecules in an early lysosomal compartment.
pubmed:affiliation
Institute of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't