Interaction between C3 and IL-2; inhibition of C3b binding to CR1 by IL-2.
Immunol Lett
; 21(2): 131-7, 1989 May.
Article
em En
| MEDLINE
| ID: mdl-2527811
ABSTRACT
We previously reported that C3 has a role in the enhancement of the IL-2 dependent proliferation of helper T cells. Because the IL-2R has a structural homology with the complement proteins, such as CR1 and CR2, we studied the possible ligand crossreactions on CR1 and IL-2-receptor, and the direct interaction between C3 and IL-2. While C3 has an enhancing effect on the IL-2 dependent proliferation of HT-2, a CR1-positive mouse T-cell line, the growth of the CTLL-16 line (CR1-negative) is not affected by C3. It has been proven that neither the insolubilized C3 nor the soluble C3b-like C3 react with the IL-2 binding epitope of the IL-2 receptor. However, using human RBC we have demonstrated that the binding of aggregated C3 to CR1 is inhibited by rIL-2, in a dose-dependent manner. When RBC were incubated with rIL-2 and FITC-labelled Fab-anti-CR1 simultaneously, there was no inhibition in the fluorescence intensity. As detected by ELISA, rIL-2 was bound to the same extent by insolubilized C3, C3b, and C3c, while C3d coat had lower binding capacity. The receptor-binding epitope of IL-2 is intact in the complex of complement proteins and rIL-2, as demonstrated by the binding of DMS1, a monoclonal antibody reacting with the receptor site of IL-2. It is strongly suggested that C3b may play a role in the growth of CR1 positive T cells.
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Base de dados:
MEDLINE
Assunto principal:
Complemento C3
/
Complemento C3b
/
Receptores de Complemento
/
Interleucina-2
Idioma:
En
Ano de publicação:
1989
Tipo de documento:
Article