Abstract: Methods and compositions are provided for the modulation of monocyte binding to endothelial cells, particularly during inflammatory episodes. Compositions are provided which bind to one or both of the monocyte surface membrane protein or the endothelial surface membrane protein which are complementary or result in the adhesion of the monocyte to the endothelial cell. The subject compositions can be used in diagnosis or therapy.

Abstract: Methods and compositions are described for modulating trafficking of leukocytes to endothelial cells involving the binding of homing receptors and addressins. Particularly, compositions are provided which can inhibit the interaction between the homing receptor and addressin or provide for directing specific molecules associated with diagnosis or treatment, where the molecules bind to the addressins.

Abstract: Novel antibodies that recognize endothelial cell surface molecules and block leukocyte extravasation are provided. These antibodies recognize tissue-specific endothelial cell surface molecules and block lymphocyte migration from the blood into tissues such as mucosal lymphoid organs and peripheral lymph nodes. Novel endothelial cell surface proteins involved in leukocyte extravasation and having a molecular weight of approximately 58,000 to 69,000 daltons and express a tissue-specific determinant are also described. The antibodies are used in an immunotherapeutic method to treat individuals having a disease or inflammation-associated pathology in which leukocyte extravasation plays a role.

Abstract: Methods and compositions are provided for determining neutrophil activation in a mammalian host by detecting the presence of shed LECAM-1 in the blood. By employing a monoclonal antibody which binds to a common epitope of lymphocyte and neutrophil LECAM-1 and a monoclonal antibody which binds to a sialylated Lewis X epitope which distinguishes between neutrophil and lymphocyte LECAM-1, the level of neutrophil activation can be determined. Various immunoassay protocols may be employed which detect the binding of the two antibodies to a common antigen.