Identification and biochemical characterization of human plasma soluble IL-7R: lower concentrations in HIV-1-infected patients. - Archive ouverte HAL Access content directly
Journal Articles Journal of Immunology Year : 2009

Identification and biochemical characterization of human plasma soluble IL-7R: lower concentrations in HIV-1-infected patients.

Abstract

The IL-7R alpha-chain and the common gamma-chain (gamma(c)) are both components of IL-7R. Human plasma harbors soluble forms of IL-7R (sIL-7Ralpha and sgamma(c)) that are detected and assayed by Western blotting, showing that the levels of sIL-7Ralpha are higher than the levels of sgamma(c) (47.5 ng/ml and 1.5 ng/ml, respectively). Gel electrophoresis and tandem mass spectrometry used to analyze deglycosylated, affinity-purified protein showed that sIL-7Ralpha is generated through differentially spliced mRNA, not by membrane receptor shedding. Plasma sIL-7Ralpha and sgamma(c) are present as heterocomplexes and sgamma(c) was found to be mainly associated with sIL-7Ralpha. The affinities of two IL-7 binding sites (K(d) = 35 +/- 8 pM and K(d) = 3 +/- 1 nM) were similar to that of the membrane receptor, suggesting that the sIL-7Ralpha/sgamma(c) complex retains high affinity for IL-7. sIL-7Ralpha mRNA is constitutively present among peripheral T lymphocytes and is down-modulated in vitro by IL-7. Chronically HIV-1-infected patients (n = 20) showed no significant (p > 0.714) variation in sgamma(c) levels and a significant (p < 0.0014) 2-fold decrease in plasma sIL-7Ralpha levels compared with those in control healthy individuals. Plasma IL-7 and sIL-7Ralpha levels did not show any obvious relationship.

Dates and versions

pasteur-00407283 , version 1 (24-07-2009)

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Thierry Rose, Olivier Lambotte, Coralie Pallier, Jean-François Delfraissy, Jean-Hervé Colle. Identification and biochemical characterization of human plasma soluble IL-7R: lower concentrations in HIV-1-infected patients.. Journal of Immunology, 2009, 182 (12), pp.7389-97. ⟨10.4049/jimmunol.0900190⟩. ⟨pasteur-00407283⟩
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