Severe inflammatory defect and reduced viability in CD18 and E-selectin double-mutant mice

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Abstract

CD18-deficient mice (CD18–/– mice) have a severe leukocyte recruitment defect in some organs, and no detectable defect in other models. Mice lacking E-selectin (CD62E–/– mice) have either no defect or a mild defect of neutrophil infiltration, depending on the model. CD18–/–CD62E–/–, but not CD18–/–CD62P–/–, mice generated by crossbreeding failed to thrive, reaching a maximum body weight of 10–15 grams. To explore the mechanisms underlying reduced viability, we investigated lethally irradiated CD62E–/– mice that were reconstituted with CD18–/– bone marrow. These mice, but not single-mutant controls, showed tenfold-increased rolling velocities in a TNF-α–induced model of inflammation. Leukocyte adhesion efficiency in CD18–/–CD62E–/– mice was reduced by 95%, and hematopoiesis was drastically altered, including severe bone marrow and blood neutrophilia and elevated G-CSF and GM-CSF levels. The greatly reduced viability of CD18–/–CD62E–/– mice appears to result from an inability to mount an adequate inflammatory response. Our data show that cooperation between E-selectin and CD18 integrins is necessary for neutrophil recruitment and that alternative adhesion pathways cannot compensate for the loss of these molecules.

Authors

S.B. Forlow, E.J. White, S.C. Barlow, S.H. Feldman, H. Lu, G.J. Bagby, A.L. Beaudet, D.C. Bullard, K. Ley