Expression of adhesion receptors other than CD99 is not affected by CD99 gene inactivation. (A) Detergent lysates of bone marrow–derived neutrophils or complete lungs from WT (^+/+), heterozygous (^+/−), or homozygous (^−/−) CD99 gene–inactivated mice were immunoblotted for CD99 or α-tubulin (as indicated). Band intensities normalized to α-tubulin control are indicated below the blots. (B) Endothelial cells isolated from skins of either WT mice or CD99^−/− mice were immunoblotted for the indicated antigens; quantification of the signals was standardized to α-tubulin signals (indicated below). (C) Fluorescence-activated cell sorting analysis of bone marrow–derived polymorphonuclear neutrophils (PMNs) of CD99^−/− (red) and WT mice (blue) for the indicated antigens; purple solid lines and light green dotted lines mark antibody-isotype controls for WT and CD99^−/− mice, respectively. VE-cad, VE-cadherin.