Adoptive immunotherapy as an in vivo model to explore antitumor mechanisms induced by a recombinant anticancer vaccine.
J Immunother
; 20(1): 48-59, 1997 Jan.
Article
em En
| MEDLINE
| ID: mdl-9101413
ABSTRACT
We have described previously the construction, generation, and in vivo biologic consequences of a recombinant vaccinia virus containing the human CEA gene (rV-CEA) in an experimental murine colon carcinoma model. Immunization of C57BL/6 mice with rV-CEA led to antigen-specific inhibition of tumor growth in both prophylactic and therapeutic settings. Although such antitumor effects were correlated with the induction of CEA-specific T-cell responses, their exact contribution in the tumor rejection mechanism remained unclear. In this study, we examined the mechanism of action of rV-CEA, with emphasis on definition of the immune cells important for such antitumor effects. To that end, a cellular adoptive transfer model was established in vivo, which allowed specific functional analysis of donor-derived immune cells in naive, sublethally irradiated, tumor-bearing recipients. Splenocytes from rV-CEA-immunized donors expressed strong antitumor activity in such tumor-bearing recipients, whereas nonimmune donor cells did not. Depletion of immune T cells before cellular transfer abolished the antitumor response. Moreover, depletion of CD8+ T cells before transfer resulted in the loss of antitumor activity, despite the presence of CD4+ T cells. In contrast, antitumor activity was demonstrable with CD8-containing, CD4-depleted effectors, although it was not as effective as with both T-cell subpopulations combined. Finally, in beta 2-microglobulin/CD8+ T-cell-deficient mice, rV-CEA immunization exerted only partial antitumor protection, compared with the immune-competent controls. Overall, we demonstrated that (a) antitumor activity induced by rV-CEA was essentially mediated by CD8+ effectors; and (b) the combination of both CD8+ and CD4+ lymphocytes led to maximal antitumor therapeutic effects, suggesting an important helper or immunoregulatory contribution of the CD4+ subset. Thus, adoptive cellular transfer strategies may have implications for both the study of recombinant anticancer vaccines and the development of potential clinical applications for cancer immunotherapy.
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Base de dados:
MEDLINE
Assunto principal:
Vacinas Sintéticas
/
Adenocarcinoma
/
Antígeno Carcinoembrionário
/
Imunoterapia Adotiva
/
Neoplasias do Colo
/
Vacinas Anticâncer
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Immunother
Assunto da revista:
ALERGIA E IMUNOLOGIA
/
NEOPLASIAS
/
TERAPEUTICA
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Estados Unidos