Increased TGF-β, Cbl-b and CTLA-4 levels and immunosuppression in association with chronic immune activation

Qibin Leng, Zvi Bentwich, Gadi Borkow

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


In this study we investigated the mechanisms mediating T-cell hyporesponsiveness in chronically immune-activated individuals. We analyzed in healthy and persistently helminth-infected individuals the relationship between immune activation and general T-cell hyporesponsiveness, T h 3/regulatory T-cell expression, transforming growth factor-β (TGF-β) secretion, CTL-associated antigen 4 (CTLA-4) levels, Casitas B-cell lymphoma-b (Cbl-b) (a negative regulator of T-cell activation) levels and phosphorylation of mitogen-activated protein kinases/extracellular signal-regulated kinase (ERK)-1 and -2. We found a very significant increase in plasma levels of TGF-β and intracellular pools of CTLA-4 and Cbl-b in association with immune activation, which correlates with decreased T-cell responses to anti-CD3 stimulation. We demonstrate that the impaired activity of ERK of peripheral T cells in highly immune-activated individuals is associated with increased levels of CTLA-4 and Cbl-b. Interestingly, in some, but not in all, of these immune-activated individuals, induction of Cbl-b intracellular pools occurs by TGF-β or CTLA-4 stimulation. We suggest that the higher levels of CTLA-4 and TGF-β, both involved in the induction of Cbl-b, point at potential mechanisms underlying general and antigen-specific immune hyporesponsiveness in chronically infected individuals.

Original languageEnglish
Pages (from-to)637-644
Number of pages8
JournalInternational Immunology
Issue number5
StatePublished - 15 May 2006


  • Anergy
  • Helminthic infections
  • Hyporesponsiveness
  • Signal transduction

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


Dive into the research topics of 'Increased TGF-β, Cbl-b and CTLA-4 levels and immunosuppression in association with chronic immune activation'. Together they form a unique fingerprint.

Cite this