Production and Evaluation of Polyclonal Antibodies in Chicken Egg Yolk against Lumpy Skin Disease Virus Vaccine

Lumpy skin disease, a highly contagious Capripoxvirus infection, leads to major economic losses in cattle globally. In Ethiopia, diagnosis relies on virus neutralization tests and PCR, emphasizing the need for serosurveillance tools that can handle large sample volumes. The objective of this study was the production and characterization of egg yolk–derived IgY antibody prototypes against the lumpy skin disease virus vaccinal strain from chicken egg yolk for the development of an enzyme-linked immunosorbent assay. The experimental study, conducted from January to May 2024 over 42 days, involved adapting the vaccinal virus on the Vero cell line and titrating it after two passages in Minimum Essential Medium. Chickens (n=10) were allocated into two groups (6 expe-rimental and 4 control), in which the experimental group received the vaccinal strain at the first shot and the booster shot on the 15th day, while the other group was inoculated with a placebo. Weekly serum and egg samples were collected, and IgY was extracted from egg yolk using polyethylene glycol, and then purified via dialysis. Antibody concentration, molecular weight, and functionality were measured using a NanoDrop spectrophotometer, SDS-PAGE, and the Virus Neutralization Test (VNT), respectively. Data was analyzed using linear regression and repeated measures one-way analysis of variance (R-ANOVA) and a linear mixed-effects model by R-4.4.1 statistical software, where (p< 0.05) indicates the threshold for a significant difference. The IgY concentration was measured, and an increase in the number of weeks significantly elevated the concentration (p = 0.0239). R-ANOVA results showed a significant difference in mean concentration across weeks (p < 0.0001), and post-hoc tests revealed significant differences in product concentration between each week. Comparison of the VNT of IgY sourced from serum and egg yolk showed substantial differences (P< 0.0002), with egg yolk IgY being more potent. This study revealed that high-affinity and high-yield IgY was generated from chicken egg yolk using LSDV vaccination, indicating that IgY technology should be adopted for developing highly specific and sensitive immunoassays.