title: Induction of tyrosine phosphorylation during ICAM-3 and LFA-1-mediated intercellular adhesion, and its regulation by the CD45 tyrosine phosphatase.
abstract: Intercellular adhesion molecule (ICAM)-3, a recently described counter-receptor for the lymphocyte function-associated antigen (LFA)-1 integrin, appears to play an important role in the initial phase of immune response. We have previously described the involvement of ICAM-3 in the regulation of LFA-1/ICAM-1-dependent cell-cell interaction of T lymphoblasts. In this study, we further investigated the functional role of ICAM-3 in other leukocyte cell-cell interactions as well as the molecular mechanisms regulating these processes. We have found that ICAM-3 is also able to mediate LFA-1/ICAM-1-independent cell aggregation of the leukemic JM T cell line and the LFA-1/CD18-deficient HAFSA B cell line. The ICAM-3-induced cell aggregation of JM and HAFSA cells was not affected by the addition of blocking mAb specific for a number of cell adhesion molecules such as CD1 1a/CD18, ICAM-1 (CD54), CD2, LFA-3 (CD58), very late antigen alpha 4 (CD49d), and very late antigen beta 1 (CD29). Interestingly, some mAb against the leukocyte tyrosine phosphatase CD45 were able to inhibit this interaction. Moreover, they also prevented the aggregation induced on JM T cells by the proaggregatory anti-LFA-1 alpha NKI-L16 mAb. In addition, inhibitors of tyrosine kinase activity also abolished ICAM-3 and LFA-1-mediated cell aggregation. The induction of tyrosine phosphorylation through ICAM-3 and LFA-1 antigens was studied by immunofluorescence, and it was found that tyrosine-phosphorylated proteins were preferentially located at intercellular boundaries upon the induction of cell aggregation by either anti-ICAM-3 or anti-LFA-1 alpha mAb. Western blot analysis revealed that the engagement of ICAM-3 or LFA-1 with activating mAb enhanced tyrosine phosphorylation of polypeptides of 125, 70, and 38 kD on JM cells. This phenomenon was inhibited by preincubation of JM cells with those anti-CD45 mAb that prevented cell aggregation. Altogether these results indicate that CD45 tyrosine phosphatase plays a relevant role in the regulation of both intracellular signaling and cell adhesion induced through ICAM-3 and beta 2 integrins.
authors.affiliation: Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma, Madrid, Spain.
authors.forename: A G
authors.initials: AG
authors.lastname: Arroyo
authors.forename: M R
authors.initials: MR
authors.lastname: Campanero
authors.forename: P
authors.initials: P
authors.lastname: Sánchez-Mateos
authors.forename: J M
authors.initials: JM
authors.lastname: Zapata
authors.forename: M A
authors.initials: MA
authors.lastname: Ursa
authors.forename: M A
authors.initials: MA
authors.lastname: del Pozo
authors.forename: F
authors.initials: F
authors.lastname: Sánchez-Madrid
mesh_terms: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D007962:Leukocytes / Q000502:physiology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology*; D019000:Phosphotyrosine; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
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; D019000:Phosphotyrosine; D014443:Tyrosine; D017493:Leukocyte Common Antigens