Tumor immunotherapy by converting tumor cells to MHC class II?positive, Ii protein?negative phenotype

Abstract

A potent antitumor CD4(+) T-helper cell immune response is created by inducing tumor cells in vivo to a MHC class II(+)/Ii(- )phenotype. MHC class II and Ii molecules were induced in tumor cells in situ following tumor injection of a plasmid containing the gene for the MHC class II transactivator (CIITA). Ii protein was suppressed by the antisense effect of an Ii-reverse gene construct (Ii-RGC) in the same or another co-injected plasmid. The MHC class II(+)/Ii(- )phenotype of the tumor cells was confirmed by FACS analysis of cells transfected in vitro and by immunostaining of tumor nodules transfected by injections in vivo. Subcutaneous Renca tumors in BALB/c mice were treated by intratumoral injection with CIITA and Ii-RGC, in combination with a subtherapeutic dose of IL-2, to up-regulate the activation of T cells. Significant tumor shrinkage and decrease in rates of progression of established Renca tumors were seen in the groups injected with Ii-RGC, compared with groups in which only IL-2 plus empty plasmid controls were injected. Our method provides an effective immunotherapy warranting further development for human cancers.

Generating MHC Class II+/Ii- phenotype after adenoviral delivery of both an expressible gene for MHC Class II inducer and an antisense Ii-RNA construct in tumor cells

“…The Ii-RGC plasmid potently inhibits Ii protein in many cell lines following lipid-mediated transient delivery or stable transfection. 8,9 In order to take advantage of the high efficiency of gene delivery by rAV, we developed rAVs to deliver Ii-RGCs into cells. MC-38 cells were infected with different concentrations of either rAV//IFN-g/Ii-RGC or rAV// IFN-g. At low concentrations (o10 MOI, Figure 4), the MHC Class II+/Ii-phenotype was induced in 490% cells with rAV/IFN-g/Ii-RGC, while rAV/IFN-g-transduced cells remained MHC Class II+/Ii+.…”

“…In vivo injection of Ii-RGC resulted in effective intratumoral immunotherapy of renal adenocarcinoma tumors. 9 In order to develop an efficient reagent for inducing MHC Class II+/Ii-tumor vaccine cells either in vitro or in situ, we have exploited the favorable characteristics of adenoviruses as vectors for our genetic constructs. Since their development in the early 1980s, recombinant adenoviruses (rAV) have been used to deliver a wide variety of genes into mammalian cells.…”

Helicobacter pyloriCagA-Dependent Macrophage Migration Inhibitory Factor Produced by Gastric Epithelial Cells Binds to CD74 and Stimulates Procarcinogenic Events

“…Patients with low CD74 expression were shown to have better outcomes than those with high CD74 expression. In more general cancer immunotherapy studies, antisense suppression of CD74 has been demonstrated to be an effective therapeutic treatment in several studies (28,29).…”

Intra-Prostate Cancer Vaccine Inducer

“…We have shown that suppression of Ii protein synthesis by antisense methods enables MHC class II molecules to present TAA epitopes to helper T cells (Hillman et al, 2003a,b;Lu et al, 2003). Expressible Ii antisense reverse gene constructs (Ii-RGC) were engineered for inclusion into DNA vaccine vectors.…”

“…Expressible Ii antisense reverse gene constructs (Ii-RGC) were engineered for inclusion into DNA vaccine vectors. These constructs were cloned into plasmids and/or engineered into adenoviruses to evaluate different methods of tumor gene transfection (Hillman et al, 2003a,b;Lu et al, 2003). The transfection of MHC class I and class II negative RM-9 cells, in vitro, using DNA plasmids encoding the genes for interferon-␥ (pIFN-␥) and the MHC class II transactivator (pCIITA) caused upregulation of MHC class I molecules and MHC class II molecules, respectively (Hillman et al, 2003b).…”