In:
The Journal of Immunology, The American Association of Immunologists, Vol. 166, No. 10 ( 2001-05-15), p. 6034-6040
Kurzfassung:
The objective of this study was to test whether CD45 signals can influence signaling processes in activated human lymphoblasts. To this end, we generated lymphoblasts which proliferate in response to common γ-chain cytokines, but readily undergo apoptosis after cytokine withdrawal. In experiments with the CD45R0 mAb UCHL-1, but not control CD45 mAbs, we found significant inhibition of proliferation. Interestingly, the pan-CD45 mAb GAP8.3, which is most effective in inhibition of OKT-3-mediated proliferation in quiescent lymphocytes, was ineffective in lymphoblasts. Addition of CD3 mAb OKT-3 had no influence on IL-2-mediated proliferation (with or without UCHL-1). In contrast, after addition of OKT-3 to IL-4- and IL-7-stimulated proliferation assays, UCHL-1 signals could not significantly alter cellular proliferation. We did not find induction of apoptosis following CD45R0 signaling. In Western blots using mAbs detecting phosphorylated STAT-3, STAT-5, STAT-6, or extracellular signal-related kinase 1/2, we found that CD45R0 signaling could effectively diminish phosphorylation of these intracellular signaling components. Using RT-PCR, we found that CD45R0 signaling inhibited IL-2 mRNA production without major influence on IL-13, IL-5, or IFN-γ mRNA levels. Costimulation with OKT-3 and IL-2 optimally induced secretion of IFN-γ, TNF-α, and IL-5, which was not decreased by CD45 signals. In conclusion, we illustrate that CD45R0 signals control early cytokine receptor-associated signaling processes and mRNA and DNA synthesis in activated human lymphoblasts. Furthermore, we show the existence of CD45 epitopes (GAP8.3), which are active and critical for signaling in quiescent lymphocytes, but are nonfunctional in activated human lymphoblasts.
Materialart:
Online-Ressource
ISSN:
0022-1767
,
1550-6606
DOI:
10.4049/jimmunol.166.10.6034
Sprache:
Englisch
Verlag:
The American Association of Immunologists
Publikationsdatum:
2001
ZDB Id:
1475085-5
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