Progesterone-induced blocking factor receptor (PIBF receptor) (PIBF receptor)

The Progesterone-induced blocking factor receptor (PIBF receptor) is a cell-surface signaling complex that mediates the immunological effects of PIBF, a protein induced by progesterone during pregnancy [1]. The receptor is characterized as a heterodimer composed of the IL-4 receptor alpha (IL-4Rα) chain and a specific PIBF-binding component, signaling primarily through the JAK/STAT pathway with a preference for STAT6 activation [2][3]. Its fundamental biological role is to facilitate maternal-fetal tolerance by shifting the immune response from a Th1-type (pro-inflammatory) to a Th2-type (anti-inflammatory) environment and inhibiting the cytolytic activity of Natural Killer (NK) cells [1][4]. Beyond its role in reproductive health, the PIBF receptor is frequently expressed in various human cancers, including breast and gastrointestinal malignancies, where it is thought to contribute to immune evasion and tumor cell survival [5]. While direct pharmacological targeting of the receptor is still largely in the experimental phase, its activity is clinically modulated indirectly via progesterone supplementation or progesterone antagonists like mifepristone [1][6].

Other names

PIBF-RPIBFRProgesterone-induced blocking factor 1 receptor

The PIBF receptor complex, upon binding its ligand, activates the JAK2/STAT6 signaling pathway, which induces a Th2 cytokine shift (increasing IL-4 and IL-10) and suppresses Natural Killer (NK) cell-mediated cytotoxicity [1][2].