TY  - JOUR
A1  - Mohamadzadeh, Mansour
A1  - Mohamadzadeh, Hamid
A1  - Brammer, Melissa
A1  - Sestak, Karol
A1  - Luftig, Ronald B.
T1  - Identification of proteases employed by dendritic cells in the processing of protein purified derivative (PPD)
T2  - Journal of immune based therapies and vaccines
N2  - Dendritic cells (DC) are known to present exogenous protein Ag effectively to T cells. In this study we sought to identify the proteases that DC employ during antigen processing. The murine epidermal-derived DC line Xs52, when pulsed with PPD, optimally activated the PPD-reactive Th1 clone LNC.2F1 as well as the Th2 clone LNC.4k1, and this activation was completely blocked by chloroquine pretreatment. These results validate the capacity of XS52 DC to digest PPD into immunogenic peptides inducing antigen specific T cell immune responses. XS52 DC, as well as splenic DC and DCs derived from bone marrow degraded standard substrates for cathepsins B, C, D/E, H, J, and L, tryptase, and chymases, indicating that DC express a variety of protease activities. Treatment of XS52 DC with pepstatin A, an inhibitor of aspartic acid proteases, completely abrogated their capacity to present native PPD, but not trypsin-digested PPD fragments to Th1 and Th2 cell clones. Pepstatin A also inhibited cathepsin D/E activity selectively among the XS52 DC-associated protease activities. On the other hand, inhibitors of serine proteases (dichloroisocoumarin, DCI) or of cystein proteases (E-64) did not impair XS52 DC presentation of PPD, nor did they inhibit cathepsin D/E activity. Finally, all tested DC populations (XS52 DC, splenic DC, and bone marrow-derived DC) constitutively expressed cathepsin D mRNA. These results suggest that DC primarily employ cathepsin D (and perhaps E) to digest PPD into antigenic peptides.
KW  - Dendritic cell
KW  - Protease activity
KW  - Protein purify derivative
KW  - Dendritic cell population
KW  - Splenic dendritic cell
Y1  - 2004
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/4332
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-11547
SN  - 1476-8518
N1  - This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
VL  - 2
IS  - 1, Art. 8
SP  - 1
EP  - 9
PB  - Biomed Central
CY  - London
ER  -