TY  - JOUR
A1  - Sheriff, Ahmed
A1  - Vogt, B.
A1  - Baumgart, Martin
A1  - Montag, C.
A1  - Hollenbach, B.
A1  - Schenk, Jörg A.
A1  - Ulrich, J.
A1  - Ellias, F.
A1  - Micheel, Burkhard
T1  - Intracellular capture of B7 in antigen-presenting cells reduces costimulatory activity
N2  - CTLA-4 gene constructs were designed to express CTLA-4 exclusively in the endoplasmic reticulum (ER). Four different CTLA-4 gene constructs were transfected into HEK 293 (human embryonic kidney) and A20 (Balb/c mouse B lymphoma) cells. All constructs contained an ER retention signal and coded for CTLA-4 expression in the ER. One of the constructs, which contained the membrane part of CTLA-4, coded for an expression both on the cell surface and in the ER. Three of the expressed CTLA-4 types (including the ER-membrane-expressed form) caused a reduced surface expression of B7 in the A20 cells. Only constructs which allow dimerization of CTLA-4 showed this effect. It is assumed that intracellular CTLA-4 bound B7 and inhibited therefore the transport of B7 to the surface. The binding obviously caused also an enhanced degradation of the complexes because both proteins showed a low concentration in the transfected cell lines. CTLA-4-transfected and B7-reduced A20 cells showed a diminished costimulating activity upon T cells. This was demonstrated by a reduced proliferation of T cells from ovalbumin-immunized Balb/c mice, incubated with ovalbumin peptide-primed CTLA-4-transfected A20 cells.
Y1  - 2003
UR  - http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBK-47T23XK- 8&_coverDate=02%2F21%2F2003&_alid=268969757&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6713&_sort=d&view=c&_acct=C000053886&_v e
ER  - 
TY  - JOUR
A1  - Hoang, Yen
A1  - Gryzik, Stefanie
A1  - Hoppe, Ines
A1  - Rybak, Alexander
A1  - Schädlich, Martin
A1  - Kadner, Isabelle
A1  - Walther, Dirk
A1  - Vera, Julio
A1  - Radbruch, Andreas
A1  - Groth, Detlef
A1  - Baumgart, Sabine
A1  - Baumgrass, Ria
T1  - PRI: Re-analysis of a public mass cytometry dataset reveals patterns of effective tumor treatments
JF  - Frontiers in immunology
N2  - Recently, mass cytometry has enabled quantification of up to 50 parameters for millions of cells per sample. It remains a challenge to analyze such high-dimensional data to exploit the richness of the inherent information, even though many valuable new analysis tools have already been developed. We propose a novel algorithm "pattern recognition of immune cells (PRI)" to tackle these high-dimensional protein combinations in the data. PRI is a tool for the analysis and visualization of cytometry data based on a three or more-parametric binning approach, feature engineering of bin properties of multivariate cell data, and a pseudo-multiparametric visualization. Using a publicly available mass cytometry dataset, we proved that reproducible feature engineering and intuitive understanding of the generated bin plots are helpful hallmarks for re-analysis with PRI. In the CD4(+)T cell population analyzed, PRI revealed two bin-plot patterns (CD90/CD44/CD86 and CD90/CD44/CD27) and 20 bin plot features for threshold-independent classification of mice concerning ineffective and effective tumor treatment. In addition, PRI mapped cell subsets regarding co-expression of the proliferation marker Ki67 with two major transcription factors and further delineated a specific Th1 cell subset. All these results demonstrate the added insights that can be obtained using the non-cluster-based tool PRI for re-analyses of high-dimensional cytometric data.
KW  - multi-parametric analysis
KW  - re-analysis
KW  - combinatorial protein
KW  - expression
KW  - high-dimensional cytometry data
KW  - mass cytometry data
KW  - pattern perception
Y1  - 2022
U6  - https://doi.org/10.3389/fimmu.2022.849329
SN  - 1664-3224
VL  - 13
PB  - Frontiers Media
CY  - Lausanne
ER  -