Cloning and expression of Se39.612 protein from Streptococcus equi

Equine strangles is a highly contagious disease which baffled the horse industry in the developed countries.We have identified a novel protein designated Se39.612 by screening a phage library of 3 kb-8 kb random DNA fragments of Streptococcus equi CF32.The inserted segment encoding the entire amino acid sequence of Se39.612 was determined by sequencing the rescued plasmids.Se39.612 gene was amplified using specific primers and cloned,and protein was expressed and purified.Strong reactivity of the protein with convalescent sera(IgG) and mucosal wash(IgA) was detected during infection,suggesting its role of humoral and mucosal responses.