title: Assay for heat-labile Escherichia coli enterotoxin using sandwich erythroimmunoassay.
abstract: We investigated the possibility of using a sheep erythrocyte-antibody conjugate as reagent in a sandwich erythroimmunoassay (SERIA) procedure to detect and titrate Escherichia coli heat-labile enterotoxin (LT) with the naked eye. In this assay, which is based on the immunological similarity between Vibrio cholerae toxin (CT) and LT, rabbit anti-CT IgG was used as immunosorbent, and sheep erythrocytes, sensitized with the rabbit anti-CT antibodies, were used as indicator. The sensitivity of the test was demonstrated by a comparative study using an enzyme-linked immunosorbent assay (ELISA). The results obtained by SERIA with 130 samples correlated well with those of a Vero cell assay and a GM1-ELISA. The test is easy, relatively cheap and as sensitive as other standard techniques; it is particularly suited for field laboratories, especially in tropical countries, and a large number of strains may be examined daily.
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis*; D002772:Cholera Toxin / Q000276:immunology; D004768:Enterotoxins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D007106:Immune Sera; D007118:Immunoassay; D012756:Sheep / Q000097:blood
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007106:Immune Sera; D002772:Cholera Toxin; C027538:heat-labile enterotoxin, E coli