The NH2-terminal domain of rat CD2 binds rat CD48 with a low affinity and binding does not require glycosylation of CD2.

Journal article

CD2, CD48 and CD58 are structurally similar cell adhesion-molecules forming a subset of the immunoglobulin superfamily (IgSF). In humans CD58 is a ligand for CD2 while in mice CD2 binds CD48. We constructed a soluble chimeric molecule comprising the extracellular portion of rat CD48 and domains 3 and 4 of rat CD4 (sCD48-CD4) and used it to examine whether CD2 is a ligand for CD48 in rats. sCD48-CD4-coated polystyrene Dynabeads formed rosettes on rat CD2-transfected COS-7 cells, and this rosetting was blocked by anti-CD2 (OX34) and anti-CD48 (OX45) monoclonal antibodies. We used sucrose-gradient ultracentrifugation to show that sCD48-CD4 binds, in solution, to soluble forms of rat CD2 including the single NH2-terminal IgSF domain of rat CD2 expressed in bacteria. The upper limit of the affinity of the rat CD48-CD2 interaction is 4 x 10(5) M-1, lower than the published affinity of human CD2 for CD58. These results show that rat CD48 binds CD2 on its NH2-terminal IgSF domain with a low affinity and that binding is independent of glycosylation.

Authors: van der Merwe, P; McPherson, D; Brown, M; Barclay, A; Cyster, J

• Publication status: Published
• Journal: European journal of immunology
• Volume: 23
• Issue: 6
• Pages: 1373-1377
• Publication date: 1993-06-01
• DOI: 10.1002/eji.1830230628
• EISSN: 1521-4141
• ISSN: 0014-2980
• Language: English
• Keywords: Rosette Formation; Receptors, Immunologic; Rats; Binding, Competitive; Animals; Antigens, Differentiation, T-Lymphocyte; Binding Sites; Structure-Activity Relationship; Protein Binding; Cell Adhesion; Ligands; Antigens, CD2; Glycosylation; Antigens, CD