The progesterone-induced blocking factor modulates the balance of PKC and intracellular Ca++

Noemi Kozma, Melinda Halasz, Tamas Palkovics, Julia Szekeres-Bartho

Research output: Contribution to journalArticle

13 Citations (Scopus)


Problem: Progesterone-induced blocking factor (PIBF) induces Th2 biased cytokine production; therefore, this study investigates the effects of PIBF on the protein kinase C (PKC)/Ca++ system - which plays a key role in Th1/Th2 differentiation. Method of study: Proteins from PIBF-treated cells were reacted on Western blots with phospho-specific antibodies recognizing different PKC izoforms. Intracellular free calcium was measured by flow cytometry. Re sults: Both interleukin (IL)-4 and PIBF induced PKC phosphorylation, which was abrogated by anti-IL-4Rα or anti-PIBF immunoglobulin G pre-treatment. PIBF treatment did not alter intracellular Ca++ levels. Inhibition of PKCζ or PKCθ phosphorylation, but not that of PKCα/β resulted in the loss of STAT6 and Jak1 phosphorylation by PIBF. Conclusions: Our data show that PIBF phosphorylates PKC via binding to the IL-4R, without affecting intracellular Ca++. Phosphorylation of PKCζ and PKCθ is required for Jak1 and STAT6 activation, whereas PKCα/β is not involved. These findings explain the mechanism by which PIBF supports a Th2 dominant cytokine pattern.

Original languageEnglish
Pages (from-to)122-129
Number of pages8
JournalAmerican Journal of Reproductive Immunology
Issue number2
Publication statusPublished - Feb 1 2006


  • Cytokine
  • Signaling
  • Th2

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Reproductive Medicine
  • Obstetrics and Gynaecology

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