Nature Immunology pages 515-522 News and Views pages 478-480
White blood cells continuously patrol the body, via the blood and lymphatic system, to defend it against invading microorganisms. Once an infection is detected, the white blood cells must migrate from the blood to the site of tissue injury. This involves the cells crossing the wall of the blood vessels in a four-step process called transmigration. Using adhesion molecules, the cells initially attach to the cell wall where they ‘roll’ or survey the cell surface. When rolling cells come into contact with signaling molecules called chemokines, the cells stop rolling and adhere more firmly to the wall of the blood vessel. In the final step the white blood cells squeeze through gaps in the wall of the blood vessels. In the June issue of Nature Immunology (Vol. 2, No. 6), scientists from Israel have discovered another step in white blood cell transmigration. They show that chemokines are not only required to stop the cells rolling but are also needed for white blood cells to squeeze though the wall of the blood vessel. In addition, continuous force or shear stress from fast flowing fluid must be applied on adherant white blood cells to facilitate migration. Thus, both signaling molecules and mechanical forces operate to allow efficient migration of white blood cells throughout the body. Francis Luscinskas, of Brigham and Women’s Hospital, discusses this paper in an accompanying News & Views. Ronen Alon Weizmann Institute of Science Department of Immunology Rehovot, 76100 ISRAEL Tel: (+972) 8-9342482 Fax: (+972) 8-9344141 ronalon@wicc.weizmann.ac.il Francis W. Luscinskas Brigham and Women's Hospital Department of Pathology LMRC Bldg, Rm 401a 221 Longwood Avenue Boston, MA 02115 UNITED STATES Tel: (+1) 617-732-6004 Fax: (+1) 617-732-5933 fluscinskas@rics.bwh.harvard.edu (C) Nature Immunology press release.
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