title: Regression of extensive pulmonary metastases in mice by adoptive transfer of antigen-specific CD8(+) CTL reactive against tumor cells expressing a naturally occurring rejection epitope.
abstract: In this study, we developed a mouse model of adoptive immunotherapy reflecting immune recognition of syngeneic tumor cells naturally expressing an endogenous rejection Ag. Specifically, in a pulmonary metastases model, we examined the potency and maintenance of an antitumor CD8(+) CTL response in vivo, as well as its effectiveness against an "extensive" tumor burden. The approach taken was to first generate tumor-specific CTL from mice challenged with the CMS4 sarcoma coadministered with anti-CTLA4 mAb, which has been shown to facilitate the induction of Ag-specific T cell responses in vivo. An H-2L(d)-restricted nonamer peptide, derived from an endogenous murine leukemia provirus was identified as a CMS4-reactive CTL epitope based upon the following: CTL cross-recognition of another syngeneic tumor cell line (CT26 colon carcinoma) previously characterized to express that gene product; sensitization of Ag-negative lymphoblasts or P815 targets with the peptide; and by cold target inhibition assays. In vivo, the adoptive transfer of CMS4-reactive CTL (> or =1 x 10(6)) resulted in nearly the complete regression of 3-day established lung metastases. Furthermore, mice that rejected CMS4 following a single adoptive transfer of CTL displayed antitumor activity to a rechallenge 45 days later, not only in the lung, but also at a s.c. distal site. Lastly, the adoptive transfer of CTL to mice harboring extensive pulmonary metastases (> 150 nodules) led to a substantial reduction in tumor burden. Overall, these data suggest that the adoptive transfer of tumor-specific CTL may have therapeutic potential for malignancies that proliferate in or metastasize to the lung.
authors.affiliation: Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Ryan
authors.forename: J A
authors.initials: JA
authors.lastname: Bristol
authors.forename: E
authors.initials: E
authors.lastname: McDuffie
authors.forename: S I
authors.initials: SI
authors.lastname: Abrams
mesh_terms: D000069594:Abatacept; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology*; D060908:CTLA-4 Antigen; D002277:Carcinoma; D002460:Cell Line; D016207:Cytokines; D005260:Female; D018796:Immunoconjugates; D016219:Immunotherapy, Adoptive / Q000379:methods*; D008175:Lung Neoplasms / Q000556:secondary* / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D012513:Sarcoma, Experimental / Q000628:therapy*; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology / Q000637:transplantation*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D016207:Cytokines; D018796:Immunoconjugates; D000069594:Abatacept