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. 2007 Jan 25;117(2):375–386. doi: 10.1172/JCI29709

Figure 8. Calreticulin and CD91 are essential for adiponectin-stimulated uptake of apoptotic cells.

Figure 8

(A) Anti-calreticulin antibody and anti-CD91 antibody inhibit adiponectin-stimulated apoptotic cell phagocytosis by macrophages. Each type of macrophage was preincubated with anti-CRT antibody or control chicken IgY or with anti-CD91 antibody or control IgG for 60 minutes. TAMRA, SE–labeled apoptotic cells were preincubated with recombinant adiponectin or vehicle, and uptake of apoptotic debris was determined by flow cytometric analysis. Data are expressed relative to control from human and THP-1 monocytes. Control human and THP-1 macrophages (anti-human macrophage antibody-positive) were 34.1% ± 0.8% and 24.9% ± 1.1% dual-positive for TAMRA, SE, respectively. **P < 0.01 versus IgY or IgG (n = 6–7). (B) Adiponectin-stimulated apoptotic cell phagocytosis by macrophages was inhibited by downregulation of calreticulin or CD91 with siRNA but not siRNA targeting the putative adiponectin receptors. The in vitro phagocytosis assay analyzed dual-positive by cells flow cytometry. Control THP-1 macrophages were 24.3% ± 1.0% positive for TAMRA, SE. **P < 0.01 versus unrelated siRNA with adiponectin (n = 6–7).