TY  - JOUR
A1  - Duschl, Albert
A1  - Jahn, Ute
A1  - Bertling, Claudia
A1  - Sebald, Walter
T1  - A comparison of assays for the response of primary human T-cells upon stimulation with interleukin-2, interleukin-4 and interleukin-7
N2  - The most commonly used assay to quantitate the response of peripheral T~cells upon stimulation with growth factors is determination of incorporated (JH]TdR. We compared thls test to three other methods: 1. direct countlog of cells with a Coulter type counter as reference assay, 2. a colorimetric assay using the tetrazolium dye 3-[ 4,S-dimethylthiazol-l-yl]-2,5diphenyl tetrazolium (MTT), which is a cheap and increasingly popular non-radioactive method and 3. incorporation of the thymidine analog 5-bromo-2'-deoxyuridine detection with a monoclonal antibody on cytospins. Primary human PHA-blasts from >30 healthy individuals were stimulated with IL-2, IL-4 aod IL-7 and assayed with up to four different methods. We discuss the advantages and disadvantages of the assays used and tbe effects of differences between cell preparations. We observed no significant variations between individuals for the dose dependence, but the relative emctency of IL4 compared to IL-2 and IL-7 was variable. This was probably due to the slower response observed upon stimulation with this factor.
KW  - T-Lymphozyt
KW  - Interleukin 2
KW  - Interleukin 4
KW  - Interleukin 7
KW  - T-cells
KW  - proliferation assays
KW  - IL-2
KW  - IL-4
KW  - IL-7
Y1  - 1992
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86750
ER  - 
TY  - JOUR
A1  - Dummer, R.
A1  - Posseckert, G.
A1  - Nestle, F.
A1  - Witzgall, R.
A1  - Burger, M.
A1  - Becker, J. C.
A1  - Schäfer, E.
A1  - Wiede, J.
A1  - Sebald, Walter
A1  - Burg, G.
T1  - Soluble interleukin-2 receptors inhibit interleukin 2-dependent proliferation and cytotoxicity: explanation for diminished natural killer cell activity in cutaneous T-cell lymphomas in vivo?
N2  - No abstract available
KW  - Biochemie
Y1  - 1992
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62473
ER  - 
TY  - JOUR
A1  - Kruse, N.
A1  - Tony, H. P.
A1  - Sebald, Walter
T1  - Conversion of human interleukin-4 into a high affinity antagonist by a single amino acid replacement
N2  - lnterleukin-4 (IL-4) represents a prototypic lymphokine (for a recent review see Paul, 1991). It promotes differentiation of B-cells and the proliferation of T- and B-cell, and other cell types of the lymphoid system. An antagonist of human IL-4 was discovered during the studies presented here after Tyr124 of the recombinant proteinbad been substituted by an aspartic acid residue. This IL-4 variant, Y124D, bound with high affinity to the IL-4 receptor (K\(_D\) = 310 pM), but retained no detectable proliferative activity for T -<:ells and inhibited IL-4-dependent T -cell proliferation competitively (K\(_i\) = 620 pM). The loss of efficacy in variant Y124D was estimated to be > 100-fold on the basis of a weak partial agonist activity for the very sensitive induction of CD23 positive B-cells. The subsitution of Tyr124 by either phenylalanine, histidine, asparagine, Iysine or glycine resulted in partial agonist variants with unaltered receptor binding atTmity and relatively small deficiencies in efficacy. These results demoostrate that high affinity binding and signal generation can be uncoupled efticiently in a Iigand of a receptor betonging to the recently identified hematopoietin receptor family. In addition we show for the first time, that a powerful antagonist acting on the IL-4 receptor system can be derived from the IL-4 protein.
KW  - Biochemie
KW  - drug design
KW  - partial agonists
KW  - receptor signalling
Y1  - 1992
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62469
ER  -