Rapid Depletion of Renal Macrophages using Human CD59/Intermedilysin Cell Ablation Tool.

Renal macrophages (RMs) are essential for kidney health, orchestrating immune surveillance, tissue homeostasis, and responses to injury. Previously, we reported the use of a human CD59 (hCD59)/intermedilysin (ILY) cell ablation tool to study the distinct fate, dynamics, and niches of RMs of bone marrow or embryonic origin. RMs originate from yolk sac-derived macrophages, fetal liver monocytes, and bone marrow-derived monocytes and are maintained in adulthood through local proliferation and recruitment of circulating monocytes. Here, we report a detailed protocol for the selective ablation of RMs to study their regeneration, including 1) generation and characterization of the Cre-inducible expression of hCD59 in mouse RMs, 2) purification of ILY and characterization of ILY activity, 3) induction of hCD59 expression on RMs in compound mice, and 4) characterization of regeneration after ILY-mediated RM ablation. ILY specifically and rapidly depletes RMs in compound mice, with efficient macrophage ablation within 1 day of ILY administration. Renal macrophage regeneration began by day 3 post-ablation, with ~88% recovery by day 7. This model offers a powerful tool for studying macrophage biology and can be used for selectively ablating other cell populations in the kidney, liver, and fatty tissues to investigate their function and regeneration.