PMID- 9780172
OWN - NLM
STAT- MEDLINE
DCOM- 19981104
LR  - 20071114
IS  - 0022-1767 (Print)
IS  - 0022-1767 (Linking)
VI  - 161
IP  - 8
DP  - 1998 Oct 15
TI  - Rapid extracellular degradation of synthetic class I peptides by human dendritic 
      cells.
PG  - 4023-32
AB  - Dendritic cells (DCs) effectively process exogenous and endogenous Ag and present 
      peptide in the context of both class I and class II molecules. We have 
      demonstrated that peripheral blood DCs efficiently degrade synthetic class I 
      peptides at their cell surface within minutes as determined by analyzing DC 
      supernatants by HPLC. Fragments were verified as bona fide cleavage products by 
      direct sequencing using collision-induced dissociation tandem mass spectrometry. 
      The predominant degradative activities were 1) not secreted but associated with 
      activity at the plasma membrane, 2) ecto-orientated, 3) not induced by 
      peptide-specific interactions, and 4) not associated with nonspecific uptake. 
      Sequence analysis indicated that both N- and C-terminal as well as 
      endoproteolytic events were occurring at the cell surface. The primary 
      exoproteolytic event was identified as CD13 or CD13-like activity through 
      inhibition studies and could be inhibited by ubiquitin and metal-chelating 
      agents. Endoproteolytic events could be inhibited in the presence of DTT, but the 
      precise nature of this enzyme is still undetermined. Compared with the starting 
      monocyte population, DCs cultured in the presence of granulocyte-macrophage 
      CSF/IL-4 exhibited the highest degradative rate (4.3 nmol/min), followed by 
      cultured monocytes (2.9 nmol/min) and freshly isolated monocytes (1.0 nmol/min). 
      In addition to increased enzymatic activity, a change in substrate specificity 
      was noted. Results are discussed with respect to APC loading, and alternatives 
      are offered for circumventing such degradation.
FAU - Amoscato, A A
AU  - Amoscato AA
AD  - Department of Surgery, University of Pittsburgh School of Medicine and University 
      of Pittsburgh Cancer Institute, PA 15213, USA. amoscato@pittsurg.nb.upmc.edu
FAU - Prenovitz, D A
AU  - Prenovitz DA
FAU - Lotze, M T
AU  - Lotze MT
LA  - eng
GR  - R011RO1CA73816-01/CA/NCI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Immunol
JT  - Journal of immunology (Baltimore, Md. : 1950)
JID - 2985117R
RN  - 0 (Histocompatibility Antigens Class I)
RN  - 0 (Membrane Proteins)
RN  - 0 (Peptides)
SB  - IM
MH  - Cell Membrane/metabolism
MH  - Cells, Cultured
MH  - Chromatography, High Pressure Liquid
MH  - Dendritic Cells/immunology/*metabolism/ultrastructure
MH  - Histocompatibility Antigens Class I/chemistry/immunology/*metabolism
MH  - Humans
MH  - Membrane Proteins/immunology/*metabolism
MH  - Peptides/chemistry/immunology/metabolism
MH  - Sequence Analysis
MH  - Substrate Specificity
EDAT- 1998/10/21 00:00
MHDA- 1998/10/21 00:01
CRDT- 1998/10/21 00:00
PHST- 1998/10/21 00:00 [pubmed]
PHST- 1998/10/21 00:01 [medline]
PHST- 1998/10/21 00:00 [entrez]
PST - ppublish
SO  - J Immunol. 1998 Oct 15;161(8):4023-32.