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1996-02-27
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Document 0175
DOCN M9630175
TI Cyclic nucleotide phosphodiesterases from purified human CD4+ and CD8+ T
lymphocytes.
DT 9603
AU Tenor H; Staniciu L; Schudt C; Hatzelmann A; Wendel A; Djukanovic R;
Church MK; Shute JK; Immunopharmacology Group, University of
Southampton, UK.
SO Clin Exp Allergy. 1995 Jul;25(7):616-24. Unique Identifier : AIDSLINE
MED/96131142
AB BACKGROUND: CD4+ and CD8+ T-lymphocytes are suggested to differentially
affect airway inflammation in asthma. Agents which increase
intracellular cAMP levels, such as PDE inhibitors, have been shown to
diminish lymphocyte growth and differentiation, and to affect cytokine
expression. Differences in the PDE isoenzyme profile between CD4+ and
CD8+ cells might form a basis to differentially modify their functions
by PDE inhibitors. OBJECTIVE: The study investigates and compares the
PDE isoenzyme activity profiles of human peripheral blood CD4+ and CD8+
T-lymphocytes. METHODS: CD4+ and CD8+ T-lymphocytes were purified (>
98%) from peripheral blood mononuclear cells by negative selection. PDE
isoenzyme activity profiles were investigated using PDE isoenzyme
selective inhibitors and activators. RESULTS: In CD4+ and CD8+
T-lymphocyte homogenates, PDE IV and PDE III activities were the
predominant PDE isoenzyme activities at 0.5 microM cyclic nucleotide
substrate concentrations. PDE IV was localized in the soluble fraction
whereas PDE III was membrane bound. Low PDE I, II and V activities were
detected. About 20% of total cAMP hydrolysing capacity at 0.5 microM
cAMP was insensitive to PDE isoenzyme selective inhibitors and
activators and therefore could not be assigned to PDE I-IV. The PDE
isoenzyme pattern was not different between CD4+ and CD8+ T-lymphocytes.
Moreover, representative inhibitors of PDE III and IV activity inhibited
cAMP hydrolysis in soluble fractions of both T-lymphocyte subsets with
similar potency. Enzyme kinetic analysis similarly did not reveal
differences between CD4+ and CD8+ T-lymphocytes. CONCLUSION: Normal CD4+
and CD8+ T-lymphocytes are likely to be equally sensitive targets for
the effects of PDE inhibitors.
DE Cell Separation CD4-Positive T-Lymphocytes/*ENZYMOLOGY CD8-Positive
T-Lymphocytes/*ENZYMOLOGY Human Isoenzymes/BLOOD Phosphodiesterase
Inhibitors/PHARMACOLOGY Phosphoric Diester Hydrolases/*BLOOD
Subcellular Fractions/ENZYMOLOGY Support, Non-U.S. Gov't
3',5'-Cyclic-GMP Phosphodiesterase/BLOOD 3',5'-Cyclic-Nucleotide
Phosphodiesterase/ANTAGONISTS & INHIB/ BLOOD JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).