Guidelines for Immunomodulatory Assays of Food Bioactives on Drosophila melanogaster Model

Food bioactives, including polyphenols (flavonoids and non‐flavonoids), phytosterols, terpenes and terpenoids, polysaccharides, alkaloids, and bioactive peptides, which are mainly present in fruits, vegetables, and meat, have exhibited multiple health benefits on the human body. The Drosophila melanogaster model provides several unique advantages for studying food‐derived immunomodulatory compounds, including a short life cycle, low cost, well‐characterized genetics, and conserved innate immune signaling pathways such as the Toll and IMD pathways. Cellular and humoral immunity are two main ways for Drosophila to combat natural pathogen infections such as viruses, bacteria, fungi, and parasites. However, the absence of an adaptive immune system and physiological differences from mammals may limit the direct translation of findings to humans. Here, we present basic and common methods to study immunomodulatory effects of food bioactives in Drosophila melanogaster, including four steps: (1) treatment with food bioactives; (2) pathogen preparation; (3) infection routes; (4) assessment of immune response. Our guidelines provide insight into how to evaluate immunomodulatory assays of food bioactives.