Development of antigen-capture enzyme-linked immunoassay for chicken Interleukin-34

Authors: NAM, HYOYOUN - US Department Of Agriculture (USDA); Lillehoj, Hyun; LEE, YOUNGSUB - US Department Of Agriculture (USDA)

Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2025
Publication Date: 3/1/2025
Citation: Nam, H., Lillehoj, H.S., Lee, Y. 2025. Development of antigen-capture enzyme-linked immunoassay for chicken Interleukin-34. Developmental and Comparative Immunology. 164. Article e105331. https://doi.org/10.1016/j.dci.2025.105331.
DOI: https://doi.org/10.1016/j.dci.2025.105331

Interpretive Summary: Lack of information concerning the role of various immune factors controlling inflammatory response following parasitic infections limits our progress to develop novel strategies to mitigate infection-induced harmful host response. In this report, ARS scientists in Beltsville discovered that a newly described host cytokine called IL-34 is involved in regulating both pro-inflammatory and anti-inflammatory responses in chickens. However, previous investigations were limited to analyzing mRNA levels due to a lack of suitable immunological tools. Unfortunately, the presence of mRNA does not always ensure corresponding protein production because of translation delays and post-transcriptional regulation. Therefore, this study was aimed to develop specific monoclonal antibodies(mAbs) and an immunoassay to quantitate IL-34 at the protein level in poultry so their role in disease process can be better investigated. The results of this study showed that new sets of mAbs detect chicken IL-34 specifically and thus these antibodies will be a valuable tool to investigate the role of IL-34 during disease process in chickens.

Technical Abstract: We generated five anti-chIL-34 mAbs that specifically recognized recombinant chIL-34 protein. Additionally, the antigen-capture ELISA developed using a combination of 12A8 and biotinylated-3G11 antibodies, demonstrated its usefulness as an immunological tool by monitoring LPS-stimulated IL-34 secretion over time in HD11 cells. Furthermore, validity of newly developed IL-34 ELISA assay was tested in a poultry disease model by monitoring the changes in IL-34 levels in the serum of chickens infected with E. maxima and E. tenella. More importantly, the newly produced mAbs specific for chIL-34 demonstrated the ability to neutralize the function of poultry IL-34. Therefore, they are expected to serve as valuable immunological reagents for elucidating the mechanisms of IL-34 in future poultry immunology research. Since IL-34 is a relatively recently discovered cytokine, its function and role in the avian immune system remain poorly understood (Hong, 2021). Consequently, research on IL-34 cytokine in avian species has generally relied on mRNA level analysis. Therefore, the novel immunological reagents presented in this study will not only facilitate enhanced IL-34 research at the protein-level in future avian studies but also complement existing mRNA-level analyses.