Evaluation of inexpensive blocking agents for ELISA in the detection of antibody in leprosy

Non-Specific Binding and Cross-Reaction of ELISA: A Case Study of Porcine Hemoglobin Detection

Different types of enzyme-linked immunosorbent assays (ELISA) have been widely used to control food safety and quality. To develop an accurate and reproducible ELISA, false immunodetection results caused by non-specific binding (NSB) and cross-reaction must be prevented. During the case study of sandwich ELISA development for the detection of porcine hemoglobin (P_Hb), several critical factors leading to NSB and cross-reaction were found. First, to reduce the NSB of the target analyte, the selection of microplate and blocker was discussed. Second, cross-reactions between enzyme-labeled secondary antibodies and sample proteins were demonstrated. In addition, the function of (3-aminopropyl)triethoxysilane (APTES) was evaluated. Overall, this study highlights the essence of both antibody and assay validation to minimize any false-positive/negative immunodetection results.

Finger-prick blood collection and computer-assisted enzyme-linked immunosorbent assay for large-scale serological studies on leprosy

An immunoglobulin M anti-phenolic glycolipid 1 assay was standardized and optimized using specimens of dried blood collected on commercial precut filter paper discs, followed by a computer-assisted enzyme-linked immunosorbent assay (ELISA). The correlation between venepuncture and finger-prick methods, the calibration of the quantity of absorbed blood, and the reproducibility of the ELISA test were excellent. A slight decline of activity was observed when the samples were stored for 3 months at +4 degrees C. Skimmed milk can be used as diluent instead of bovine serum albumin, contributing to lessening the cost of the test. Using the method described, as many as 300 samples can be collected in the field and 480 ELISAs per day can be run in the central laboratory by one trained person.