AIF-1 and RNASET2 Play Complementary Roles in the Innate Immune Response of Medicinal Leech
Basic science / preclinical published in Journal of innate immunity (2019)
Abstract
Recent studies demonstrated that allograft inflammatory factor-1 (AIF-1) and RNASET2 act as chemoattractants for macrophages and modulate the inflammatory processes in both vertebrates and invertebrates. The expression of these proteins significantly increases after bacterial infection; however, the mechanisms by which they regulate the innate immune response are still poorly defined. Here, we evaluate the effect of bacterial lipopolysaccharide injection on the expression pattern of these genes and the interrelation between them during innate immune response in the medicinal leech, an invertebrate model with a simple anatomy and a marked similarity with vertebrates in inflammatory processes. Collectively, prokaryotic-eukaryotic co-cultures and in vivo infection assays suggest that RNASET2 and AIF-1 play a crucial role in orchestrating a functional cross-talk between granulocytes and macrophages in leeches, resulting in the activation of an effective response against pathogen infection. RNASET2, firstly released by granulocytes, likely plays an early antibacterial role. Subsequently, AIF-1+ RNASET2-recruited macrophages further recruit other macrophages to potentiate the antibacterial inflammatory response. These experimental data are in keeping with the notion of RNA-SET2 acting as an alarmin-like molecule whose role is to locally transmit a "danger" signal (such as a bacterial infection) to the innate immune system in order to trigger an appropriate host response.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Recent studies demonstrated that allograft inflammatory factor-1 (AIF-1) and RNASET2 act as chemoattractants for macrophages and modulate the inflammatory processes in both vertebrates and invertebrates.
Why This Matters for Hirudotherapy
Using the medicinal leech as an invertebrate immune model, this study examined how the chemoattractant proteins AIF-1 and RNASET2 respond to bacterial lipopolysaccharide, finding through prokaryotic-eukaryotic co-cultures and in vivo infection assays that RNASET2 is released early by granulocytes as an alarmin-like antibacterial signal and that AIF-1-positive macrophages are then recruited to amplify the inflammatory response. For ASH this supports the broader scientific narrative that Hirudo medicinalis is a tractable model whose inflammatory processes show marked similarity to vertebrates, helping explain the leech's well-characterized innate-immune and bioactive-molecule biology. The caveat is that this is basic preclinical mechanism work in the leech itself, not a study of any human therapeutic effect, and it makes no clinical claims.
Citation
AIF-1 and RNASET2 Play Complementary Roles in the Innate Immune Response of Medicinal Leech.
Baranzini N et al. · Journal of innate immunity, 2019
Added to ASH library: March 18, 2026 · Site last updated: June 18, 2026