Impaired phagocytic mechanism in annexin 1 null macrophages

<jats:p> <jats:list list-type="explicit-label"> <jats:list-item><jats:p>The role of the anti‐inflammatory protein annexin‐A1 (Anx‐A1) in the phagocytic process has been investigated using a murine bone marrow culture‐derived macrophage model from <jats:italic>Anx‐A1</jats:italic><jats:sup>+/+</jats:sup> and <jats:italic>Anx‐A1</jats:italic><jats:sup>−/−</jats:sup> mice.</jats:p></jats:list-item> <jats:list-item><jats:p>Macrophages prepared from <jats:italic>Anx‐A1</jats:italic><jats:sup>−/−</jats:sup> mice exhibited a reduced ingestion of zymosan, <jats:italic>Neisseria meningitidis</jats:italic> or sheep red blood cells, when compared to <jats:italic>Anx‐A1</jats:italic><jats:sup>+/+</jats:sup> cells and in the case of zymosan this effect was also mirrored by a reduced clearance <jats:italic>in vivo</jats:italic> when particles were injected into the peritoneal cavity of <jats:italic>Anx‐A1</jats:italic><jats:sup>−/−</jats:sup> mice.</jats:p></jats:list-item> <jats:list-item><jats:p>The ablation of the Anx‐A1 gene did not cause any apparent cytoskeletal defects associated with particle ingestion but the cell surface expression of the key adhesion molecule CD11b was depressed in the <jats:italic>Anx‐A1</jats:italic><jats:sup>−/−</jats:sup> cells providing a possible explanation for the attenuated phagocytic potential of these cells.</jats:p></jats:list-item> <jats:list-item><jats:p>The production of the cytokines TNF<jats:italic>α</jats:italic> and IL‐6 was increased in <jats:italic>Anx‐A1</jats:italic><jats:sup>−/−</jats:sup> macrophages following phagocytosis of all types of particle.</jats:p></jats:list-item> </jats:list> </jats:p><jats:p><jats:italic>British Journal of Pharmacology</jats:italic> (2006) <jats:bold>148</jats:bold>, 469–477. doi:<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" xlink:href="10.1038/sj.bjp.0706730">10.1038/sj.bjp.0706730</jats:ext-link></jats:p>