ABSTRACT
The equal importance of the qualitative and quantitative characteristics of antigen presentation as well as the set of costimulatory signals provided by antigen presenting cells to T-cells in determining the outcome of T-cell responses at the time of antigen recognition is now clear. Moreover, an important function in innate mechanisms has been recently attributed to costimulatory molecules demonstrating their relevant role in different stages of immune response. In this paper, we demonstrated the ability of CD40L (CD154) and CD80 costimulatory molecules expression in a T-cell lymphoma to induce both T-cell dependent and independent immune responses leading to an important anti-tumor effect. CD40 expression by LBC cells enhanced only T-cell dependent anti-tumor immune response resulting in tumor rejection. Furthermore, this work represents the first report to describe complete tumor rejection after co-inoculation of lymphoma cells transfected with CD40L and CD80 in either presence or absence of CD40 expressing lymphoma cells. In addition, this synergistic effect resulted in long lasting immunity to parental tumor cells. Co-inoculation of tumor cells each genetically modified to express a different costimulatory molecule circumvents the need to co-transfect genetically unstable tumor cells and represents an option for those weakly or non-immunogenic tumors where either treatment alone proved to be inefficient. This strategy represents a promising approach for inducing anti-tumor immunity and provides a new rational design of cancer therapies.
Subject(s)
B7-1 Antigen/metabolism , CD40 Antigens/metabolism , CD40 Ligand/metabolism , Graft Rejection , Lymphoma, T-Cell/immunology , Neoplasms, Experimental/immunology , Receptors, Antigen, T-Cell/metabolism , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Animals , Cancer Vaccines/immunology , Cell Line, Tumor , Cytotoxicity, Immunologic , Lymphocyte Activation , Lymphoma, T-Cell/therapy , Mice , Mice, Inbred BALB C , Mice, NudeABSTRACT
In transfection protocols, the expression levels of the transgene is important to define, still is difficult to obtain in certain cell lines such as those derived from T-lymphoma cells. In this study we evaluate transgene expression kinetics in the presence and absence of two well known transcription activators such as phorbol-12-myristate13-acetate (PMA) and Ionomicin (IO). Three murine T lymphoma cell lines (LBC, EL4 and BW5147) were transfected by electroporation using green fluorescent protein (GFP) as a reporter gene and analyzed by flow cytometry. Addition of PMA/IO resulted in a significant increase of the Mean Fluorescence Intensity but not in GFP-positive cell percentages, either in transient or stable transfected LBC and EL4 cells. Remarkable, BW5147 cells showed low GFP induction with a significant increment only in stable transfected cells. Our results demonstrated that CMV promoter activity can be enhanced in transfected lymphoma cells by PMA/IO suggesting that transgene expression levels can be optimized by means of the use of transcription activators.