Purpose To investigate the use of a new high-dielectric constant (HDC) material for improving SNR and transmission efficiency for clinical MRI applications at 3T with cervical spine imaging. Materials and Methods Human subjects were imaged using a commercial cervical spine receive array coil on a clinical system with and without pads containing Barium Titanate beads in deuterium water placed around the neck. Numerical electromagnetic field simulations of the same configuration were also performed. Results Experimental and simulated maps of transmit and receive fields showed greater efficiency for imaging the cervical spine when the pads were present. Experimental measurements showed a significant improvement in SNR with the pads present and an average input power reduction of 46%. Conclusion Use of HDC material can enhance SNR and transmission efficiency for clinical imaging of the cervical spine at 3.0 T.

Cationic lipid DNA complex (CLDC) is an immunostimulatory preparation that has significant anti-leukemic effects in multiple murine models of leukemia: BCR-ABL(+) myelogenous leukemia in C3H/HeJ animals and myelomonocytic leukemia in BALB/c mice. Following leukemic challenge, CLDC treatment inhibits tumor cell growth in vivo and extends survival, sometimes resulting in apparent eradication of tumor cells. CLDC induces multiple cytokines including interferon-gamma (IFNγ), and intravenous treatment results in a more rapid and robust response than subcutaneous treatment. IFNγ is induced in a dose-dependent manner, and tachyphylaxis results from repeated doses of CLDC. Tachyphylaxis of therapeutic effects is exacerbated at higher doses, thus the optimal survival benefits are seen at intermediate doses. Animals whose leukemia has been successfully treated with CLDC exhibit a survival advantage when faced with a secondary leukemic challenge, suggesting the existence of an adaptive anti-leukemic response. This work demonstrates the effectiveness of CLDC in multiple experimental leukemias and is consistent with a stimulation of a lasting TH(1) anti-leukemic immune response.

We developed a method to in vitro prime and expand WT1-specific CD8+ T cells using a WT1 peptide mix which could facilitate the expansion of WT1 specific T cells from donors of different HLA backgrounds. Monocyte-derived dendritic cells or PBMC isolated from 4 normal donors were pulsed with WT1 overlapping peptides prior to T cell stimulation. CD8 selected T cells were primed using WT1 peptide pulsed dendritic cells and then re-stimulated 11 days later using WT1 peptide pulsed autologous PBMC. IL-7 and IL-2 were added to the T cell cultures 4 days after the first stimulation to promote CTL differentiation. 7 days after the second CD8 stimulation, WT1 specificity was measured by tetramer staining. All donors exhibited tetramer positive T cells (donor 1=3.11%, donor 2=6.32%, donor 3=2.17%, donor 4=1.08%). WT1-specific cytotoxicity measured by 51Cr-release assays was also assayed 7 days post the second stimulation; however, WT1-specific cytotoxicity was not observed. WT1-specific CD8 T cells from 3 of the 4 donors were cloned and enriched by limited dilution. Clones were removed from OKT3 and WT1-specific cytotoxicity was measured in 51Cr-release assays. At least 1 clone from each of the 3 donors exhibited WT1 specific cytotoxicty (donor 1=54%, donor 2=20%, donor 3=26%). In conclusion, CD8 selected PBMC stimulated by antigen presenting cells pulsed with a WT1 peptide mix stained positive for HLA-A2 WT1-tetramers and exhibited WT1-specific cytotoxicity after cloning and subsequent expansion.

WT1 responsive CTL were generated from CMVpp65 stimulated CD8 cells isolated from three CMV-seropositive HLA-A2 normal donors. CD8 selected T cells were stimulated with dendritic cells pulsed with CMVpp65 overlapping peptides. 10 days after the primary stimulation, CD8 T cells were restimulated with CMV pp65 peptide pulsed PBMC. The CMV-stimulated CTL exhibited CMV-specific but not WT1-specific cytotoxicity after the second stimulation as measured by 51CR release assay (Donor 1=54% and 7%, Donor 2=77% and 14%). However, all CMV-stimulated CTL stained with PE-RMFPNAPYL, a WT1A2 tetramer (Donor 1=2.51%, Donor 2=3.85%, Donor 3=0.49%). EBV-CTL generated from an HLA-A2 donor, and WT1 CTL generated from a non-HLA-A2 donor did not stain with the WT1A2 tetramer (0.02% and 0.01% respectively). Therefore, the WT1A2 tetramer was cross-reactive with pp65-CTL and exhibited HLA-A2 specificity. To enrich the CMV-CTL WT1A2 tetramer staining population, we PE-selected donor 1 PE-WT1 tetramer binding pp65 stimulated CTL. The WT1-selected cells were cloned by limiting dilution. 7 of 8 WT1-selected clones stained with the WT1A2 tetramer ranging from 0.89%-3.56%. WT1-selected clones showed three types of specific cytotoxicity: 1) against pp65-only (3 clones=22-34%), 2) against WT1-only (2 clones=43-44%), or 3) against both WT1 and CMV (1 clone=55% and 24% respectively). 2 of the 8 clones did not exhibit either WT1 or CMV specific cytotoxicity. Only 1 of the 2 clones that exhibit WT1 specific cytotoxicity exhibited WT1-specifc IFN-γ production, as measured by ELISPOT. All clones that displayed CMV-specific cytotoxicity also exhibited CMV-specific IFN-γ production. To our knowledge this is the first description of WT1 cross-reactive, CMV-specific CTL.