Direct Expression of the Extracellular Portion of Human FcεRIα Chain as Inclusion Bodies in Escherichia coli

Abstract

The extracellular portion of the α chain of the human high-affinity IgE receptor (FcεRIα) was expressd as inclusino bodies in Escherichia coli. In immunoblot analysis, two bands were reactive to human IgE and mouse anti-human FcεRIα monoclonal antibodies. N-terminal sequencing showed that the two bands were equivalent to the soluble FcεRIα with a methionine residue at the N-terminus (Met-1-172) and 23-172, in which the N-terminal 22 residues of the soluble FcεRIα have been removed, possibly by degradation in E. coli cells. IgE-binding to CHO cells expressing FcεRI was inhibited by the addition of the recombinant products prepared by the refolding procedure from inclusion bodies. The system for the expression of soluble human FcεRIα in E. coli presented in this study and its further improvement would be useful for the production of the protein as a potent therapeutic and for analysis of the IgE-FcεRIα interaction.

• allergy
• high-affinity IgE receptor
• Escherichia coli
• expression system
• inclusion body