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Updated: Aug 9, 2026

Laminar Flow-based Assays to Investigate Leukocyte Recruitment on Cultured Vascular Cells and Adherent Platelets
08:50

Laminar Flow-based Assays to Investigate Leukocyte Recruitment on Cultured Vascular Cells and Adherent Platelets

Published on: April 9, 2018

The junctional adhesion molecule 3 (JAM-3) on human platelets is a counterreceptor for the leukocyte integrin Mac-1

Sentot Santoso1, Ulrich J H Sachs, Hartmut Kroll

  • 1Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig-University, D-35385 Giessen, Germany. sentot.santoso@immunologie.med.uni-giessen.de

The Journal of Experimental Medicine
|September 5, 2002
PubMed

The recently described junctional adhesion molecules (JAMs) in man and mice are involved in homotypic and heterotypic intercellular interactions. Here, a third member of this family, human JAM-3, was identified and described as a novel counterreceptor on platelets for the leukocyte beta2-integrin Mac-1 (alphaMbeta2, CD11b/CD18). With the help of two monoclonal antibodies, Gi11 and Gi13, against a 43-kD surface glycoprotein on human platelets, a full-length cDNA encoding JAM-3 was identified. JAM-3 is a type I transmembrane glycoprotein containing two Ig-like domains. Although JAM-3 did not undergo homophilic interactions, myelo-monocytic cells adhered to immobilized JAM-3 or to JAM-3-transfected cells. This heterophilic interaction was specifically attributed to a direct interaction of JAM-3 with the beta2-integrin Mac-1 and to a lower extent with p150.95 (alphaXbeta2, CD11c/CD18) but not with LFA-1 (alphaLbeta2, CD11a/CD18) or with beta1-integrins. These results were corroborated by analysis of K562 erythroleukemic cells transfected with different heterodimeric beta2-integrins and by using purified proteins. Moreover, purified JAM-3 or antibodies against JAM-3 blocked the platelet-neutrophil interaction, indicating that platelet JAM-3 serves as a counterreceptor for Mac-1 mediating leukocyte-platelet interactions. JAM-3 thereby provides a novel molecular target for antagonizing interactions between vascular cells that promote inflammatory vascular pathologies such as in atherothrombosis.

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