Guoping  Liu, Liuqun  Hu, Meng-Yuan  Liu, Li-Xin  Ma, 
    Fusion of FedF and SLT-IIe B Subunit is an Candidate Antigen Against Edema 
  Disease of Swine,
    Journal of Animal and Veterinary Advances,
    Volume 12,Issue 18,
    2013,
    Pages 1461-1467,
    ISSN 1680-5593,
    javaa.2013.1461.1467,
    (https://makhillpublications.co/view-article.php?doi=javaa.2013.1461.1467)
    Abstract: The DNA sequence encoding the truncated SLT-IIeB and FedF of the <I>Escherichia coli</I> Ee strain which is the major immunogenic fragment for the edema disease in piglets were subcloned and fused to the C terminus of Glutathione S-Transferase (GST) in a pGEX-KG expression vector, to obtain a fusion protein expression plasmid pKSF. Fusion protein was expressed as inclusion body. The anti-serum of GST-SF was able to restrain the toxicity of SLT-IIe to Vero-E6 cells and inhibit the adhesion of F18 fimbriae to the porcine small intestinal brush border cells <I> in vitro</I>. SPF KM mice were vaccinated subcutaneously at 0 and 2 weeks with 25 &#956;g GST-SF, GST-B and GST-F, respectively and were challenged with 5 times the LD<SUB>50</SUB> volume of the Ee strain. The IgG titers against SLT-IIeB or FedF in the GST-SF group were higher and were maintained for a longer time compared to the GST-B and GST-F groups. GST-SF can induce a better immune response and can provide the protection rate of the 70%. These results show the fusion protein GST-SF had stronger immunogenicity and better protective effects against the Ee strain and thus can be used for vaccination against the edema disease of swine.
    Keywords: Ee strain;SLT-IIeB;FedF;fusion expression;immunogenicity