Signal transduction by B7/BB1 expressed on activated T lymphocytes: cross-linking of B7/BB1 induces protein tyrosine phosphorylation and synergizes with signalling through T-cell receptor/CD3.
Immunology
; 86(2): 155-61, 1995 Oct.
Article
em En
| MEDLINE
| ID: mdl-7490112
ABSTRACT
We report here that B7/BB1 molecules expressed on activated T lymphocytes are involved in signal transduction. Anti-B7/BB1 monoclonal antibody (mAb) enhanced allogeneic proliferative responses against three different B lymphoma lines in a dose-dependent manner, while the same mAb inhibited T-cell response against allogeneic T cells expressing B7/BB1. Induction of B7/BB1 expression on T cells with allogeneic stimulation was confirmed by flow cytometric analysis. With the purified preactivated T cells as responder cells, anti-B7/BB1 mAb costimulated these primed T cells with coimmobilized anti-CD3 mAb. Moreover, cross-linking of B7/BB1 molecules induced protein tyrosine phosphorylation in preactivated T cells with a phosphorylation pattern distinct from those induced by signalling through other T-cell molecules. These results suggest that B7/BB1 molecules function not only as costimulatory ligands expressed on antigen-presenting cells but as receptors on T cells to transduce the costimulatory signals into the cells and may play a role for T-cell-T-cell interactions leading to clonal expansion of activated T lymphocytes. However, the physiological relevance of our finding remains to be explored.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tirosina
/
Glicoproteínas de Membrana
/
Ativação Linfocitária
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Linfócitos T
/
Transdução de Sinais
/
Antígenos CD
Limite:
Humans
Idioma:
En
Revista:
Immunology
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Japão