Drosophila Helical factor is an inducible protein acting as an immune-regulated cytokine in S2 cells

► The role of Drosophila Helical factor (Hf) as a cytokine was studied. ► Hf expression is increased after immune challenge. ► Recombinant Hf increases the expression of antimicrobial peptides. ► Hf is a potential new candidate as a Drosophila cytokine.