Background Epsilon toxin (ETX) causes a commonly fatal enterotoxemia in domestic animals. Also, ETX causes serious economic losses to animal husbandry. In this study, we selected several clones against ETX using repertoires displayed on filamentous phage. Anti-ETX specific clones were enriched by binding to immobilized antigen, followed by elution and re-propagation of phage. After multiple rounds of binding selection, ELISA analysis showed that most isolated clones had high affinity and specificity for ETX. Results Two recombinant monoclonal antibodies against ETX were isolated by phage display technology. B1 phage VH antibody isolated from DAb library and G2 soluble scFv antibody isolated from Tomlinson I + J libraries have been applied as the capture and detection antibodies for developing an ETX sandwich ELISA test, respectively. Conclusions Designed ETX sandwich ELISA could be a valuable tool for quantitative detection of ETX in inactivated commercial vaccines against enterotoxemia. Graphical abstract

Background: Epsilon toxin (ETX) causes a commonly fatal enterotoxemia in domestic animals and causing serious economic losses to animal husbandry. In this study, we selected several clones against ETX using repertoires displayed on filamentous phage. Anti-ETX specific clones were enriched by binding to immobilized antigen, followed by elution and re-propagation of phage. After multiple rounds of binding selection, we evidenced that most isolated clones had high affinity and specificity for the ETX by ELISA.Results: We isolated two recombinant monoclonal antibodies against ETX by phage display technology and Using the B1 phage VH antibody isolated from DAb library as capture antibody and G2 soluble scFv antibody isolated from Tomlinson I + J libraries as the detector antibody, we developed a sandwich ELISA test.Conclusions: This sandwich ELISA could be a good candidate for quantitative detection ETX with the detection range of 5 ~ 100000 ng/ml in inactivated commercial vaccines against enterotoxemia.

Background: Epsilon toxin (ETX) causes a commonly fatal enterotoxemia in domestic animals. Also, ETX causes serious economic losses to animal husbandry. In this study, we selected several clones against ETX using repertoires displayed on filamentous phage. Anti-ETX specific clones were enriched by binding to immobilized antigen, followed by elution and re-propagation of phage. After multiple rounds of binding selection, ELISA analysis showed that most isolated clones had high affinity and specificity for ETX.Results: Two recombinant monoclonal antibodies against ETX were isolated by phage display technology. B1 phage VH antibody isolated from DAb library and G2 soluble scFv antibody isolated from Tomlinson I+J libraries have been applied as the capture and detection antibodies for developing an ETX sandwich ELISA test, respectively.Conclusions: Designed ETX sandwich ELISA could be a valuable tool for quantitative detection of ETX in inactivated commercial vaccines against enterotoxemia.

Background: Epsilon toxin (ETX) causes a commonly fatal enterotoxemia in domestic animals. Also, ETX causes serious economic losses to animal husbandry. In this study, we selected several clones against ETX using repertoires displayed on filamentous phage. Anti-ETX specific clones were enriched by binding to immobilized antigen, followed by elution and re-propagation of phage. After multiple rounds of binding selection, ELISA analysis showed that most isolated clones had high affinity and specificity for ETX.Results: Two recombinant monoclonal antibodies against ETX were isolated by phage display technology. B1 phage VH antibody isolated from DAb library and G2 soluble scFv antibody isolated from Tomlinson I+J libraries have been applied as the capture and detection antibodies for developing an ETX sandwich ELISA test, respectively. Conclusions: Designed ETX sandwich ELISA could be a valuable tool for quantitative detection of ETX in inactivated commercial vaccines against enterotoxemia.