Transfusion of CD206⁺ M2 Macrophages Ameliorates Antibody-Mediated Glomerulonephritis in Mice

Macrophages are multifunctional immune cells that may either drive or modulate disease pathogenesis, depending on the activated phenotype. In this study, we investigated the protective effects of CD206⁺ M2 macrophages against nephrotoxic serum nephritis in mice. We found that these immunosuppressive macrophages, derived from bone marrow and stimulated with IL-4/IL-13 [CD206⁺ M2 bone marrow–derived macrophages (M2BMMs)], protected against renal injury, decreased proteinuria, and diminished the infiltration of CD68⁺ macrophages, neutrophils, and T cells into glomerular tissue. Comparable therapeutic results were obtained with CD206⁺ M2 cells derived from induced pluripotent stem cells. Notably, CD206⁺ M2BMMs, which retained an M2 signature, could elicit a switch of M1 to M2 phenotype in co-cultured macrophages. Moreover, these cells were found to induce the production of regulatory T cells in the spleen and renal draining lymph node. Accordingly, mRNA expression of the T helper 1 cytokines tumor necrosis factor-α, interferon-β, interferon-γ, and IL-12 was significantly reduced in kidneys from mice treated with CD206⁺ M2BMMs. Taken together, the data suggest that CD206⁺ M2 may have therapeutic potential against antibody-mediated glomerular injury and presents its therapeutic value for the treatment of crescentic nephritis in humans.