Chronic chemoimmunotherapy achieves cure of spontaneous murine mammary tumors via persistent blockade of posttherapy counter-regulation.
J Immunol
; 187(8): 4109-18, 2011 Oct 15.
Article
em En
| MEDLINE
| ID: mdl-21908736
ABSTRACT
Intratumoral delivery of IL-12 and GM-CSF induces local and systemic antitumor CD8(+) T cell activation and tumor kill. However, the effector response is transient and is rapidly countered by CD4(+) Foxp3(+) T suppressor cell expansion. To determine whether depletion of the pre-existing T suppressor cell pool prior to treatment could diminish posttherapy regulatory cell resurgence, FVBneuN mice bearing advanced spontaneous mammary tumors were treated with cyclophosphamide (CY) 1 d before IL-12/GM-CSF therapy. Administration of CY mediated a significant delay in the post-IL-12/GM-CSF T suppressor cell rebound, resulting in a 7-fold increase in the CD8(+) CTL/T suppressor cell ratio, a 3-fold enhancement of CTL cytotoxicity, and an extension of the effector window from 3 to 7 d. In long-term therapy studies, chronic chemoimmunotherapy promoted a dramatic enhancement of tumor regression, resulting in complete cure in 44% of the mice receiving CY plus IL-12/GM-CSF. Tumor eradication in the chronic therapy setting was associated with the ability to repeatedly rescue and maintain cytotoxic CD8(+) T cell activity. These findings demonstrated that chronic administration of CY in conjunction with immune therapy enhances the initial induction of antitumor T effector cells and, more importantly, sustains their cytotoxic activity over the long-term via persistent blockade of homeostatic counter-regulation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator Estimulador de Colônias de Granulócitos e Macrófagos
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Interleucina-12
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Ciclofosfamida
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Imunoterapia
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Neoplasias Mamárias Experimentais
Limite:
Animals
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article