Preincubation with anti-CD4 influences activation of human T cells by subsequent co-cross-linking of CD4 with CD3.
J Leukoc Biol
; 54(5): 430-8, 1993 Nov.
Article
em En
| MEDLINE
| ID: mdl-8228621
ABSTRACT
Under physiological conditions, T cell activation by major histocompatibility complex (MHC)-antigen complexes requires engagement of both the T cell receptor (TcR) and the CD4 (or CD8) accessory molecules. It has been shown, however, that ligation of CD4 and CD8 can also inhibit T cell activation in an MHC-independent way. Therefore, the role of CD4 in T cell activation and the mechanism of the suppression of T cell functions by anti-CD4 are as yet unclear. We activated T cells by CD4/CD3 co-cross-linking and studied the effect of preincubation with anti-CD4 on this activation. We show here that anti-CD4 effects T cell activation in a complex, time-dependent manner. Whereas short preincubations with anti-CD4 usually enhanced T cell proliferation in response to subsequent co-cross-linking of CD3 with CD4, longer preincubations led to its decrease. The observed suppression of proliferation after a long preincubation with anti-CD4 was apparently due to impairment of TcR signaling, as assessed by measurement of Ca2+ mobilization and tyrosine phosphorylation in T cells. These results add a temporal element to the previously observed synergism between the TcR and CD4 in T cell activation.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ativação Linfocitária
/
Linfócitos T
/
Antígenos CD4
/
Complexo CD3
/
Anticorpos Monoclonais
Limite:
Humans
Idioma:
En
Ano de publicação:
1993
Tipo de documento:
Article