Study on the reaction of Maltose binding protein-Protein A (MBP-Protein A) fusion protein with the immunoglobulin of some animal species

    Staphylococcus aureus protein A, as a cell wall protein of the bacterium, belongs to a group of bacterial proteins with binding specificity for the IgG molecule. Recently, we cloned and expressed the protein A gene of Staphylococcus aureus in E.coli, as a fusion protein with maltose binding protein (MBP-Protein A). After purification, the expressed protein was also labeled with peroxidase. The aim of this study was to evaluate the reaction of this recombinant protein A with the immunoglobulin of some animal species. Based on the results of ELISA and immunodot, the labeled protein A was able to bind cat and dog IgGs. The reactivity of the protein with cattle and horse IgGs was weak and it reacted poorly with sheep IgG. This protein did not react with chicken IgG. In this study, the ability of the expressed protein A labeled with peroxidase, for detection of E.coli specific antibodies in cat and dog sera was demonstrated by indirect ELISA. In conclusion, the recombinant MBP-protein A is biologically active and could be used in immunological assays at least for certain animal species.