Cognate CD4 T-cell licensing of dendritic cells heralds anti-cytomegalovirus CD8 T-cell immunity after human allogeneic umbilical cord blood transplantation.

UNLABELLED: Reactivation of human cytomegalovirus (CMV) is hazardous to patients undergoing allogeneic cord blood transplantation (CBT), lowering survival rates by approximately 25%. While antiviral treatment ameliorates viremia, complete viral control requires CD8+ T-cell-driven immunity. Mouse studies suggest that cognate antigen-specific CD4+ T-cell licensing of dendritic cells (DCs) is required to generate effective CD8+ T-cell responses. For humans, this was not fully understood. We here show that CD4+ T cells are essential for licensing of human DCs to generate effector and memory CD8+ T-cell immunity against CMV in CBT patients. First, we show in CBT recipients that clonal expansion of CMV-pp65-specific CD4+ T cells precedes the rise in CMV-pp65-specific CD8+ T cells. Second, the elicitation of CMV-pp65-specific CD8+ T cells from rare naive precursors in cord blood requires DC licensing by cognate CMV-pp65-specific CD4+ T cells. Finally, also CD8+ T-cell memory responses require CD4+ T-cell-mediated licensing of DCs in our system, by secretion of gamma interferon (IFN-γ) by pp65-specific CD4+ T cells. Together, these data show that human DCs require licensing by cognate antigen-specific CD4+ T cells to elicit effective CD8+ T-cell-mediated immunity and fight off viral reactivation in CBT patients. IMPORTANCE: Survival rates after stem cell transplantation are lowered by 25% when patients undergo reactivation of cytomegalovirus (CMV) that they harbor. Immune protection against CMV is mostly executed by white blood cells called killer T cells. We here show that for generation of optimally protective killer T-cell responses that respond to CMV, the early elicitation of help from a second branch of CMV-directed T cells, called helper T cells, is required.

Multi-cistronic vector encoding optimized safety switch for adoptive therapy with T-cell receptor-modified T cells.

T-cell receptor (TCR) gene transfer is an attractive strategy to equip T cells with defined antigen-specific TCRs using short-term in vitro procedures to target both hematological malignancies and solid tumors. TCR gene transfer poses different safety issues that might warrant the inclusion of a suicide gene. High affinity TCRs may result in on-target toxicity, and off-target reactivity directed against healthy tissue can be observed due to mixed TCR dimers. Inclusion of a suicide gene as a safety switch may abrogate these unwanted toxicities. Human CD20 has been proposed as a nonimmunogenic suicide gene targeted by widely used clinical-grade anti-CD20 antibodies that can additionally function as a selection marker. However, transduction of T cells with a multi-cistronic vector encoding both TCR and CD20 resulted in poor coexpression. In this study, we demonstrated that codon optimization of TCR and CD20 resulted in profound coexpression of both the preferentially expressed antigen in melanoma (PRAME)-TCR and CD20, allowing selective as well as efficient elimination of these engineered T cells in vitro. These results demonstrate the great potential of codon optimized CD20 to be broadly used in clinical trials as a safety switch.

Apical root resorption of upper incisors during the torquing stage of the tip-edge technique.

The purpose of this study was to investigate whether treatment with the Tip-Edge appliance resulted in more apical root resorption (ARR) of the central and lateral incisors during the torquing (third stage) than the non-torquing phases (first two stages) of orthodontic treatment. The three stages of this orthodontic technique make it possible to examine the amount of root shortening during torque separately from other types of tooth movement. The ARR ratio was calculated in 31 Caucasian patients (20 females, 11 males), after the non-torquing stage of treatment and after the torquing phase, by analysing periapical radiographs taken at the beginning of treatment (T1), before the start of the torquing stage (T2), and at the end of treatment (T3). At T1, the mean age was 13 years 6 months (+/- 3 years 3 months). The mean, standard deviation and range of the ARR ratios were calculated and compared (P < 0.001). T-tests were performed to determine levels of significance, at different stages of treatment, between teeth with and without ARR (ARR ratio = 1). Root shortening at T3 was observed for 70 per cent of the central and 76 per cent of the lateral incisors. At T2, ARR was 48 and 53 per cent, respectively. Compared with T2, 38 per cent of the central incisors and 55 per cent of the lateral incisors showed ARR during the application of torque. At T3, the finding for both was 22 per cent. The mean ARR ratio for the central and lateral incisors was the same after the non-torquing stage of treatment but was significantly different from a tooth with no root resorption. After the torquing stage, the ARR ratio for the central incisors was 0.96 and for lateral incisors 0.92. At the end of treatment, the ratio was 0.89 and 0.85, respectively. This study revealed that both the central and the lateral incisors showed comparable amounts of ARR during the torquing and non-torquing stage of Tip-Edge treatment.

Anterior tooth morphology and its effect on torque.

This study was undertaken to determine the variation in crown-root angle (CRA) of the upper incisors and canines as well as the variation in their labial contour. In addition, the influence of the variability of the labial contour and of different bracket heights on torque was evaluated. Proximal radiographs were taken of 160 extracted maxillary teeth (81 incisors and 79 canines). They were digitized and analysed with Jasc Paint Shop Pro 7TM and Mathcad 2001 Professional. The incisal edge, the centre of the cemento-enamel junction (CEJ), and the root apex were digitized to define the crown and root long axis. For all teeth the CRA was measured. At several heights of the labial surface a tangent was determined, enabling measurement of the inclination of the labial surface. The CRA had great variability, ranging from 167 to 195 degrees for the canines (mean value 183 degrees) and from 171 to 195 degrees for the incisors (average 184 degrees). The mean inclinations of the labial surfaces for the incisors varied greatly. Between 4 and 4.5 mm from the incisal edge the standard deviations (SD) were the smallest and between 2 and 4.5 mm from the incisal edge the labial surface angle differed by approximately 10 degrees. For the canines the mean inclinations of the buccal surface also varied. This angle differed by around 10 degrees between 2 and 4.5 mm from the incisal edge, but the SD were much larger than for the incisors. It can be concluded that placement of a bracket on a tooth at varying heights, still within a clinically acceptable range, results in important differences in the amount of root torque.

The long-term effect of delayed graft function on cadaveric renal transplants treated with low-dose cyclosporine.

We evaluated the long-term effect of delayed graft function (DGF) on cadaveric renal transplant patients treated with "low-dose" cyclosporine (CsA). Between January 1985 and December 1986, 103 cadaveric renal transplants were performed. Patients were divided into 3 groups, depending upon graft function 3 days posttransplantation (PT): 1) no DGF with serum creatinine (SCr) levels less than 2 mg/dl, 2) moderate DGF with SCr of 2.0-6.9 mg/dl, and 3) severe DGF with SCr of more than 7.0 mg/dl. Overall actuarial graft survival rates for 1, 2, 3, and 4 years PT were 86, 75, 69, and 69%, respectively. Graft survival rates were the same for the 3 DGF groups at all times up to 4 years PT. Initially, renal function was best in the no DGF group, but there was no effect of DGF on renal function in any of the 3 groups 2-4 years PT. We conclude that DGF does not effect the long-term results of cadaveric renal transplants when "low-dose" CsA and prednisone are used as immunosuppressive agents.