IMEX   05356
INSTITUTO DE MEDICINA EXPERIMENTAL
Unidad Ejecutora - UE
artículos
Título:
Anti-inflammatory pretreatment enables an effcient dendritic cell-based immunotherapy against established tumors
Autor/es:
PAULA CHIARELLA; MARISA VULCANO; JUAN BRUZZO; MÓNICA VERMEULEN; SILVIA VANZULLI; ANDREA MAGLIOCO; GABRIELA CAMERANO; VÍCTOR PALACIOS; GABRIELA FERNÁNDEZ; ROMINA FERNÁNDEZ BRANDO; MARTÍN A. ISTURIZ; GRACIELA I. DRAN; OSCAR D. BUSTUOABAD; RAÚL A. RUGGIERO
Revista:
CANCER IMMUNOLOGY IMMUNOTHERAPY
Referencias:
Año: 2007 p. 701 - 718
ISSN:
0340-7004
Resumen:
Abstract Although animals can be immunized against
the growth of some tumor implants, most of the attempts to
use immunotherapy to cause the regression of animal and
human tumors once they have become established have
been disappointing even when strongly immunogenic
tumors were used as target. In this paper, we demonstrate
that the failure to achieve an efficient immunological
treatment against an established strongly immunogenic
murine fibrosarcoma was paralleled with the emergence of
a state of immunological unresponsiveness (immunological
eclipse) against tumor antigens observed when the tumor
surpassed the critical size of 500 mm3. In turn, the onset of
the immunological eclipse was coincidental with the onset
of a systemic inflammatory condition characterized by a
high number of circulating and splenic polymorphonucleated
neutrophils (PMN) displaying activation and
Gr1+Mac1+ phenotype and an increasing serum concentration
of the pro-inflammatory cytokines TNF-_, IL-1_ and
IL-6 cytokines and C-reactive protein (CRP) and serum A
amyloid (SAA) phase acute proteins. Treatment of tumorbearing
mice with a single low dose (0.75 mg/kg) of the
synthetic corticoid dexamethasone (DX) significantly
reduced all the systemic inflammatory parameters and
simultaneously reversed the immunological eclipse, as evidenced
by the restoration of speciffic T-cell-dependent
concomitant immunity, ability of spleen cells to transfer
anti-tumor activity and recovery of T-cell signal transduction
molecules. Two other anti-inflammatory treatments by
using indomethacin or dimeric TNF-_ receptor, also partially
reversed the immunological eclipse although the
effect was not as striking as that observed with DX. The
reversion of the immunological eclipse was not enough on
its own to inhibit the primary growing tumor. However,
when we used the two-step strategy of inoculating DX to
reverse the eclipse and then dendritic cells loaded with
tumor antigens (DC) as an immunization booster, a significant
inhibition of the growth of both established tumors and
remnant tumor cells after excision of large established
tumors was observed, despite the fact that the vaccination
alone (DC) had no effect or even enhanced tumor growth
in certain circumstances. The two-step strategy of tumor
immunotherapy that we present is based on the rationale that it is necessary to eliminate or ameliorate the immunological
eclipse as a precondition to allow an otherwise
ineVective anti-tumor immunological therapy to have a
chance to be successful.