Primate Monocytes - CD14, CD16 - Ziegler-Heitbrock

Abstract Characterization of Fc epsilonRI expressing human monocytic cell lines. 1. The role of CD45 on signal transduction in primary monocytes and cell lines.

Abstract

Background: Recently, the high affinity receptor far IgE (Fc epsilon RI), which plays a major role in allergies, has been identified on a number of different antigen presenting cell types, including human monocytes from atopic and nonatopic donors. In this report human monocytic cell lines were used to test for the expression of Fc epsilon RI, reasoning that a monocytic cell line expressing Fc epsilon RI constitutively would be a useful tool for large scale studies on the regulation of IgE binding and signal transduction. Methods: Reverse transduction polymerase chain reaction was applied to identify Fc epsilon RI alpha chain message, flow cytometry to detect Fc epsilon RI surface expression and signal transduction on the cell lines generated by transfection. Results: We report the establishment of monocytic cell lines constitutively expressing Fc epsilon RI (THP1 alpha 01 to THP1 alpha 40) generated by transfection of the cell line THP1 with a plasmid encoding the Fc epsilon RI alpha chain only. Fc epsilon RI on the THP1 alpha lines specifically binds IgE and is functional with regard to ligand binding and signal transduction. Comparative studies between the transfectants and primary human monocytes from nonatopic donors demonstrated the regulatory role of the tyrosine phosphatase CD45 on Fc epsilon RI mediated cell activation. Conclusions: Monocytic cell lines carry Fc epsilon RI alpha chain RNA and enhancement by transfection results in surface Fc epsilon RI expression on THP1. Triggering the receptor on the THP1 alpha lines or on human monocytes, which express native Fc epsilon RI, elicits a rapid and transient calcium mobilization, prevented by co cross linking of Fc epsilon RI and CD45.