Development and Evaluation of a Blocking Lateral Flow Assay Strip for Detection of Newcastle Disease Virus Antibodies

Figures

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  Figure 1. The schematic representation of the bLFA strip. The bLFA strip included three pads (sample, conjugate, and absorbent), a nitrocellulose (NC) membrane, and a PVC plate. The conjugate pad contained the dried gold-labeled mAb, which provided an easily visible red color. There were two blots of chicken anti-NDV polyantibody IgG and SPA for the T- and C-lines on the NC membrane, respectively.

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  Figure 2. Determination of the bLFA strip sensitivity. The 2-fold serially diluted chicken NDV hyperimmunized serum sample was incubated with the HN protein solution for 10 min, and the mixtures were then applied to the blocking lateral flow bLFA strip and placed horizontally for 10 min to observe the result (a), and the colored membranes were screened by a TSR-3000 Reader, and the relative optical density (ROD) values of T-lines were analyzed by AIS software (b). Note: B: blank control is a strip containing protein and no serum samples; P: PBS control is a strip only containing phosphate-buffered saline.

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  Figure 3. Determination of the bLFA strip specificity. The serum samples of the related avian viruses including AI (H5, H7, H9 subtypes), IB, EDS, MD, and AD, as well as ND positive serum and negative serum (N) were tested by the bLFA strip. Meanwhile, the HN detection antigen mixed with PBS is used as a blank control (B).

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  Figure 4. The dynamic change in NDV antibody in infected and vaccinated chickens. Serum samples were collected from the F48E8-infected and LaSota-vaccinated chickens at 1, 2, 4, 5, 9, and 13 DPI post-infected. The anti-NDV antibody titers of sera were then detected by the bLFA strip and HI test, respectively.