| The reference Escherichia coli (Kcoli) strain 2134 (0157 : H19) and 107/86 (0139 : K12 : HI), which express fimbriae F18ac and F18ab respectivly, were inactivated by 0.1% formaldehyde. Spleen-derived B cells from the BALB/c mouse injected with the inactivated bacterial antigen were fused with SP2/0 myeloma cells. By the tests of slide agglutination, eleven hybridoma cell lines were obtained, which were denominated as 1B3,1B7,1E3,2E9,3B2,3C2,3C3,4D7, 5E9,5H4 and 6C4 respectively. Slide agglutination showed that two of these 11 monoclonal antibodies (McAbs), 3B2 and 5E9, were against the common antigenic determinant of F28 fimbriae, designated "a". Three of these McAbs, 1B3, 3C2 and 3C3, were F18 "b" antigenic epitopes specific. Six of these McAbs, 1B7,1E3,2E9,4D7, 5H4 and 6C4, were F18 "c" factor specific. The antibodies from culture supernatants had titers of 1 : 23~1 : 26, in the direct agglutination test (DA), and those from the mouse ascitic fluid had titers of 1 : 26~1 : 2~13 in DA. All these McAbs do not agglutinate with reference E.coli strains for F4 F5 F6 F41 adhesins or other F18 fimbriae negative E coli strains and SalmonellaThe McAbs had been primarily used in slide agglutinations to detect F18 fimbriae antigens of 64 field isolates collected from pigs with postweaning diarrhea and/or edema disease, all of these 64 isolates harboured fed A gene coded the major subunit of F18 fimbriae. 34.37% (22/64) of these isolates were identified as F18 fimbriae positive when cultured in Trypticase Soy Broth (TSB) cultures. 95.5% (21/22) of these F18 positive stains were F18ac positive, and 4.5% (1/22) was F18ab positive. Meanwhile their O serogroups included the usual serotypes 0139, and the unusual serotvpes O107 and O116, et al. The results suggested that F18 fimbriae maybe the usual surface antigens on Kcoli strains isolated from pigs with postweaning diarrhea and edema disease.
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