ABSTRACT
BACKGROUND: M290SAP, a murine CD103 antibody conjugated with the immunotoxin saporin, has been found to induce the indefinite acceptance of transplanted pancreatic islets in mice. We sought to understand the underlying mechanism of this alloacceptance, particularly with respect to the CD4 CD25 T regulatory phenotype. METHODS: In this study, we established the kinetics of M290SAP and evaluated the requirement of alloantigen for the induction and maintenance of CD4 CD25 T regulatory cells (Tregs). Naive C57BL/6 mice were treated with several doses of M290SAP with and without donor-specific blood or splenocytes. Blood and spleens were collected at specific time points and underwent FACS analysis. RESULTS: M290SAP significantly depleted CD103 cells and induced the up-regulation of CD4 CD25 T regulatory population in spleen cell preparations. The combination of alloantigen in the form of donor-specific blood or splenocytes, with M290SAP, further induced the up-regulation of CD4 CD25 Tregs in the spleen compared with either M290SAP alone or alloantigen alone. The generation of CD4 CD25 cells and the depletion of CD103 cells reached a maximum at 7 d and by 3 wk CD103 and CD4 CD25 T regulatory cell populations returned to baseline. When multiple antigenic challenges were administered, the splenic CD4 CD25 cell population was again up-regulated and persisted for 3 wk. CONCLUSION: Our data confirm that M290SAP induces the generation of the CD4 CD25 T regulatory phenotype in spleens of naïve mice. Alloantigen further enhances and rejuvenates the CD4 CD25 cell population in mice treated with M290SAP.
Subject(s)
Antibodies, Monoclonal/pharmacology , Antigens, CD/immunology , Integrin alpha Chains/immunology , Islets of Langerhans Transplantation , T-Lymphocytes, Regulatory/drug effects , Transplantation Tolerance/drug effects , Animals , Antibodies, Monoclonal, Murine-Derived , Female , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Phenotype , T-Lymphocytes, Regulatory/metabolism , Transplantation, Homologous , Up-RegulationABSTRACT
We have shown that a diet containing freeze-dried black raspberries (BRB) inhibits the development of chemically induced cancer in the rat esophagus. To provide insights into possible mechanisms by which BRB inhibit esophageal carcinogenesis, we evaluated an ethanol (EtOH) extract of BRB, and two component anthocyanins (cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside) in BRB, for their effects on growth, apoptosis, and gene expression in rat esophageal epithelial cell lines. The EtOH extract and both anthocyanins selectively caused significant growth inhibition and induction of apoptosis in a highly tumorigenic cell line (RE-149 DHD) but not in a weakly tumorigenic line (RE-149). The uptake of anthocyanins from the EtOH extract into RE-149 DHD cells far exceeded their uptake into RE-149 cells, which may have accounted for the selective effects of the extract on growth and apoptosis of RE-149 DHD cells. The growth inhibitory and proapoptotic effects were enhanced by the daily addition of the EtOH extract and the anthocyanins to the medium. Interestingly, the EtOH extract did not alter cyclooxygenase-2 (COX-2) and nitric oxide synthase (i-NOS) expression in RE-149 DHD cells, whereas both anthocyanins downregulated the expressions of these genes. This differential effect may have been related to the relative amounts of anthocyanins in the extract vs. when they were added individually to the medium. We conclude that the selective effects of the EtOH extract on growth and apoptosis of highly tumorigenic rat esophageal epithelial cells in vitro may be due to preferential uptake and retention of its component anthocyanins, and this may also be responsible for the greater inhibitory effects of freeze-dried whole berries on tumor cells in vivo.
