TY - JOUR
T1 - Rapid activation‐independent shedding of leukocyte L‐selectin induced by cross‐linking of the surface antigen
AU - Palecanda, Aiyappa
AU - Walcheck, Bruce
AU - Bishop, D. Keith
AU - Jutila, Mark A.
PY - 1992/5
Y1 - 1992/5
N2 - L‐selectin (also termed LAM‐1, Leu‐8, TQ‐1, gp90MEL‐14, peripheral lymph node homing receptor and LECAM‐1) is an adhesion protein thought to be important in leukocyte entry into lymphoid tissues and sites of inflammation. We, as well as others, have shown that leukocyte activation by chemotactic factors results in rapid shedding (release) of L‐selectin from the cell surface. Here we have used flow cytometry, enzyme‐linked immunosorbent assay, and SDS‐PAGE/Western blot analysis to determine whether cross‐linking of L‐selectin in the absence of activation causes shedding. We found that rapid loss of leukocyte L‐selectin expression (down‐regulation) could be induced by treating cells with a chemical cross‐linker [bis (sulfosuccinimidyl) suberate]. L‐selectin down‐regulation via cross‐linking could occur at 4°C and in the absence of detectable cell activation (increased expression of CD11b/18). The loss of L‐selectin expression was due to shedding of the molecule from the leukocyte cell surface. Cross‐linking of L‐selectin with specific monoclonal antibodies also caused loss of surface expression of L‐selectin at 37°C. Finally, shed L‐selectin was detected in the plasma of healthy adults whose peripheral blood leukocytes demonstrated no obvious signs of activation. Our results suggest that activation‐independent shedding of leukocyte L‐selectin may occur in vivo and a possible mechanism could involve cross‐linking of leukocyte L‐selectin. This provides a novel mechanism for rapid regulation of expression of a leukocyte‐endothelial cell adhesion receptor.
AB - L‐selectin (also termed LAM‐1, Leu‐8, TQ‐1, gp90MEL‐14, peripheral lymph node homing receptor and LECAM‐1) is an adhesion protein thought to be important in leukocyte entry into lymphoid tissues and sites of inflammation. We, as well as others, have shown that leukocyte activation by chemotactic factors results in rapid shedding (release) of L‐selectin from the cell surface. Here we have used flow cytometry, enzyme‐linked immunosorbent assay, and SDS‐PAGE/Western blot analysis to determine whether cross‐linking of L‐selectin in the absence of activation causes shedding. We found that rapid loss of leukocyte L‐selectin expression (down‐regulation) could be induced by treating cells with a chemical cross‐linker [bis (sulfosuccinimidyl) suberate]. L‐selectin down‐regulation via cross‐linking could occur at 4°C and in the absence of detectable cell activation (increased expression of CD11b/18). The loss of L‐selectin expression was due to shedding of the molecule from the leukocyte cell surface. Cross‐linking of L‐selectin with specific monoclonal antibodies also caused loss of surface expression of L‐selectin at 37°C. Finally, shed L‐selectin was detected in the plasma of healthy adults whose peripheral blood leukocytes demonstrated no obvious signs of activation. Our results suggest that activation‐independent shedding of leukocyte L‐selectin may occur in vivo and a possible mechanism could involve cross‐linking of leukocyte L‐selectin. This provides a novel mechanism for rapid regulation of expression of a leukocyte‐endothelial cell adhesion receptor.
UR - http://www.scopus.com/inward/record.url?scp=0026522926&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026522926&partnerID=8YFLogxK
U2 - 10.1002/eji.1830220524
DO - 10.1002/eji.1830220524
M3 - Article
C2 - 1374339
AN - SCOPUS:0026522926
SN - 0014-2980
VL - 22
SP - 1279
EP - 1286
JO - European Journal of Immunology
JF - European Journal of Immunology
IS - 5
ER -