title: Epitope mapping and functional properties of anti-intercellular adhesion molecule-3 (CD50) monoclonal antibodies.
abstract: Intercellular adhesion molecule-3 (ICAM-3, CD50), a member of the immunoglobulin gene superfamily, is a major ligand for the lymphocyte function-associated antigen 1 (LFA-1, CD18/CD11a) in the resting immune system and plays a role as a signaling and costimulatory molecule on T lymphocytes. In this study we have generated a large panel of anti-ICAM-3 monoclonal antibodies (mAb) and show that the biological effects of these antibodies are critically dependent on the epitope recognized. By using an adhesion assay employing COS cells expressing LFA-1 binding to recombinant chimeric ICAM-3-Fc proteins (which overcomes the confounding effects of interleukocyte LFA-1/ICAM binding events), we have been able to examine the effects of these antibodies in blocking LFA-1/ICAM-3 adhesion. Our data suggests that only a small minority of ICAM-3 mAb, recognizing a distinct epitope, are able to mimic the effects of LFA-1 binding to ICAM-3. Moreover these antibodies are functionally distinct as defined by their costimulatory activity and ability to elicit interleukin-2 production and cell proliferation in T lymphocytes.
authors.affiliation: Cell Adhesion Laboratory, Imperial Cancer Research Fund, Institute of Molecular Medicine, Nuffield.
authors.forename: D
authors.initials: D
authors.lastname: Bossy
authors.forename: C D
authors.initials: CD
authors.lastname: Buckley
authors.forename: C L
authors.initials: CL
authors.lastname: Holness
authors.forename: A J
authors.initials: AJ
authors.lastname: Littler
authors.forename: N
authors.initials: N
authors.lastname: Murray
authors.forename: I
authors.initials: I
authors.lastname: Collins
authors.forename: D L
authors.initials: DL
authors.lastname: Simmons
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000502:physiology; D015703:Antigens, CD; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules / Q000276:immunology* / Q000502:physiology; D002449:Cell Aggregation; D002460:Cell Line; D018604:Epitope Mapping; D006801:Humans; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules; C483616:ICAM3 protein, human; D016169:Lymphocyte Function-Associated Antigen-1