Development of monoclonal antibodies and immunoassays for sensitive and specific detection of Shiga toxin Stx2f.
BACKGROUND
Shiga toxin 2 (Stx2) is a major virulence factor in gastrointestinal diseases caused by Escherichia coli. Although Stx2a (prototypical Stx2) is well-studied, all seven subtypes of Stx2 have been associated with disease in mammals. Several subtypes of Stx2, including Stx2f, are difficult to detect immunologically.


RESULTS
Four novel monoclonal antibodies (mAbs) against the Stx2f subtype were produced and characterized. These mAbs react exclusively to the Stx2f A subunit, and do not cross-react with other subtypes of Stx2. A Stx2f-specific sandwich ELISA was established and a limit of detection of 0.123 ng/mL was obtained using one pair of the mAbs. The receptor preference of Stx2f was confirmed using this sandwich ELISA. Three out of four mAbs can partially neutralize the toxicity of Stx2f in a cell-based assay. These mAbs were also demonstrated to be highly specific and reactive when applied to colony immunoblot assays.


CONCLUSIONS
Novel mAbs specific to Stx2f were developed for the first time, providing new assets for the STEC community. Immunoassays with improved sensitivity and specificity will be useful for the detection of Stx2f present in food, environmental, and clinical samples.
Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, Albany, California, United States of America.
Craig
C
Skinner
Stephanie
S
Patfield
Larry
L
Stanker
Xiaohua
X
He
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D057134:Antibodies, Neutralizing / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D002460:Cell Line; D002645:Chickens; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D004926:Escherichia coli / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards*; D051379:Mice; D012680:Sensitivity and Specificity; D022641:Shiga Toxin 2 / Q000276:immunology*
D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D022641:Shiga Toxin 2