FIG. 4.
M2r macrophages protect NOD mice from T1D by protecting pancreatic β-cells. A: IL-4/IL-10/TGF-β–stimulated macrophages (2.5 × 106) (M2r, blue, n = 12), untreated macrophages (M0, red, n = 8), or vehicle (PBS, black, n = 8) were intraperitoneally injected into 16-week-old prediabetic NOD mice (arrow). The M2r-treated group was significantly protected compared with M0 and PBS groups, as independently statistically analyzed using the Mantel-Cox test in a Kaplan-Meier survival graph. These results are representative data from two independent experiments with a similar outcome. B: Organs were stained with anti-insulin (red) and anti-CD3 (green)–specific antibodies prior to three-dimensional reconstruction using optical projection tomography. Yellow represents colocalization of CD3 and insulin staining, indicating insulitis. Organs from 16-week-old mice represent three individual animals; 21- and 26-week-old organs represent two individual animals. C: After M2r or M0 macrophage transfer, pancreata were dissected 8 weeks later (24 weeks of age), and cryosections were stained with anti-insulin (red) and anti-CD3 (green) (n = 5). D: Insulin+ islets were counted manually from the sections in two to five transverse sections per animal to obtain the average number of insulin+ islets per section (n = 4). *P < 0.05. (A high-quality digital representation of this figure is available in the online issue.)