Expression Of Porcine Immunoglobulin G Fc Receptor Ⅱ (Fc γRⅡ) On The COS-7 Cells

Fc receptors (FcR) are a group of important molecules expressed on the surface of immune accessory and effector cells, which bind the Fc region of immunoglobulins with specific affinities and have a number of important biological functions. FcRs play a crucial role in immune regulation by providing a link between the humoral and cellular immune responses. Three classes of FcγR (FcγRI, II, III), present in human and mouse, are the best characterized.The porcine FcγRII cDNA wasl488 bp, encoding a 297 amino acid trans-membrane glycoprotein composed of two immunoglobulin-like extracelluar domains, a trans-membrane region and a cytoplasmic tail with an immunoreceptor tyrosine-based inhibitory motif (ITIM). The predicted amino acid sequence of swFcγRII was found to be 67% and 52% identitical with human and mouse FcγRIIB. RT-PCR indicated porcine FcγRII transcripts expressed in PBLs.In order to express the receptor on cell surface, a cDNA for the complete coding region of swFcγRII was subcloned into the expression vector pcDNA3, and then transfected into COS-7 cells. The COS-7 cells transfected with the swFcγRII cDNA were able to bind chicken erythrocytes sensitized using porcine IgG. Identification of porcine FcγRII will aid in the understanding IgG-FcγR interactions, and may help in developing new immunization protocols.