Guoping  Liu, Liqun  Hu, Mengyuan  Liu, Lixin  Ma, Bin  Wu, 
    Development of a FedF Based Enzyme-Linked Immunosorbent Assay for the Detection of Antibodies Against F18<SUP>+</SUP> <I>Escherichia coli</I>,
    Journal of Animal and Veterinary Advances,
    Volume 12,Issue 21,
    2013,
    Pages 1583-1589,
    ISSN 1680-5593,
    javaa.2013.1583.1589,
    (https://makhillpublications.co/view-article.php?doi=javaa.2013.1583.1589)
    Abstract: Post-weaning diarrhea or edema in piglets caused by F18<SUP>+</SUP> 
  <I>Escherichia coli</I> (<I>E. coli</I>) is a disease which is spreading worldwide; 
  however, due to the lack of a quick and convenient Assay Method, very little 
  data is available about its epidemiology. In this study, a FedF-based indirect 
  Enzyme-linked Immunosorbent Assay (ELISA) was developed which employed a fragment 
  of the FedF protein of F18<SUP>+</SUP> <I>E. coli</I> expressed through genetic 
  engineering. The optimal concentration for the purified protein was found to 
  be 2.25 &#956;g mL<SUP>-1</SUP> with an optimal serum dilution of 1:40. The 
  positive cut-off was established to be 0.381. This FedF ELISA showed high specificity 
  toward F18<SUP>+</SUP> <I>E. coli</I> positive sera and no cross reactivity 
  with positive sera against a variety of other swine pathogens, especially several 
  other <I>E. coli</I> pathogens and other major diarrhea causing pathogens. This 
  FedF-ELISA and an extracted F18 fimbriae antigen based Dot-blot assay were used 
  to assay 146 sera. The two methods showed a total agreement ratio of 93.0%. 
  Seroconversion of experimental infected pigs showed that the sensitivities of 
  the FedF-ELISA and of the Dot-blot assay were approximately equal. The FedF-based 
  ELISA was found to have both specificity and sensitivity for detection of porcine 
  antibodies.
    Keywords: seroconversion;pig;ELISA;FedF;18+ E. coli