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Intravenous Immunoglobulins Suppress Immunoglobulin Productions by Suppressing Ca2+ ‐Dependent Signal Transduction Through Fc γ Receptors in B Lymphocytes

1994; Wiley; Volume: 40; Issue: 1 Linguagem: Inglês

10.1111/j.1365-3083.1994.tb03430.x

1365-3083

N Kondo, K Kasahara, T. KAMEYAMA, Yasunori Suzuki, Nobuyuki Shimozawa, Shunji Tomatsu, Y. Nakashima, Tomohiro Hori, Akihiko Yamagishi, Takuya Ogawa, Hisashi Iwata, Yukitoshi Takahashi, RYO TAKENAKA, K Watanabe, M. HAGA, T Orii,

Immune Cell Function and Interaction

A high dose intravenous immunoglobulin (IVIG) therapy is used in the treatment of a wide range of autoimmune disorders. However, the mechanisms of the action of IVIGs remain poorly understood. To analyse the mechanisms of effects of IVIGs on immunoglobulin (Ig) production of B cells, the effects of IVIGs on B lymphoblastoid cell lines transformed by Epstein-Barr virus (LCLs) were investigated. The productions of IgG or IgM of LCLs were dose-dependently suppressed by polyethylene glycol (PEG)-treated IVIG or pH 4-treated IVIG though the productions were not or only slightly suppressed by pepsin-treated IVIG. The suppression by IVIGs was blocked by anti-human IgG Fc or anti-Fc gamma RII. C mu gene expression and mu s C terminal gene expression of LCLs were suppressed by PEG-treated IVIG, whereas neither C mu gene expression nor mu s C terminal gene expression of LCLs were suppressed by pepsin-treated IVIG. Although the increase in intracellular calcium concentration in LCLs was not suppressed by pepsin-treated IVIG, the increase was suppressed by PEG-treated IVIG. This suppressing effect of PEG-treated IVIG on intracellular calcium concentration of LCLs was blocked by anti-human IgG Fc or anti- Fc gamma RII. Our results suggest that IVIGs suppressed the Ca(2+)-dependent signal transduction through Fc gamma R on B-cell membrane, consequently, the transcription of C mu mRNA, especially secreted mu mRNA was suppressed in the B cells.