Mechanism of immune dysfunction in cancer mediated by immature Gr-1+ myeloid cells.
J Immunol
; 166(9): 5398-406, 2001 May 01.
Article
em En
| MEDLINE
| ID: mdl-11313376
ABSTRACT
The mechanism of tumor-associated T cell dysfunction remains an unresolved problem of tumor immunology. Development of T cell defects in tumor-bearing hosts are often associated with increased production of immature myeloid cells. In tumor-bearing mice, these immature myeloid cells are represented by a population of Gr-1(+) cells. In this study we investigated an effect of these cells on T cell function. Gr-1(+) cells were isolated from MethA sarcoma or C3 tumor-bearing mice using cell sorting. These Gr-1(+) cells expressed myeloid cell marker CD11b and MHC class I molecules, but they lacked expression of MHC class II molecules. Tumor-induced Gr-1(+) cells did not affect T cell responses to Con A and to a peptide presented by MHC class II. In sharp contrast, Gr-1(+) cells completely blocked T cell response to a peptide presented by MHC class I in vitro and in vivo. Block of the specific MHC class I molecules on the surface of Gr-1(+) cells completely abrogated the observed effects of these cells. Thus, immature myeloid cells specifically inhibited CD8-mediated Ag-specific T cell response, but not CD4-mediated T cell response. Differentiation of Gr-1(+) cells in the presence of growth factors and all-trans retinoic acid completely eliminated inhibitory potential of these cells. This may suggest a new approach to cancer treatment.
Buscar no Google
Base de dados:
MEDLINE
Assunto principal:
Sarcoma Experimental
/
Células Mieloides
/
Tolerância Imunológica
Limite:
Animals
Idioma:
En
Revista:
J Immunol
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos