High‐level expression of the trucated α chain of Human high‐affinity receptor for IgE as a soluble form by baculovirus‐infected insect cells

Open Access
Publisher Website
Google Scholar
Abstract
The binding subunit of human high‐affinity receptor for IgE (FcɛRI α) was efficiently expressed as a truncated form in insect cells. The soluble (s)FcɛRI α purified from culture medium by affinity chromatography with an anti‐(α chain) mAb was nearly homogeneous and had an IgE‐binding activity. The amino acid composition and the revealed N‐terminal amino acid sequence of sFcɛRI α suggested that it was properly processed in insect cells. The apparent molecular mass (35 kDa) of purified sFcɛRI α was smaller than that of sFcɛRI α produced by CHO transfectants. The reduction of the apparent molecular mass after N‐glycanase treatment showed the recombinant product was N‐glycosylated. Peptide mapping of native and deglycosylated sFcɛRI α indicated that three Asn residues (Asn21, Asn42 and Asn 166) should be almost fully glycosylated, and that two Asn residues (Asn 74 and Asn 135) were partially glycosylated.