Invariant NKT Cells From Donor Lymphocyte Infusions (DLI-iNKTs) Promote ex vivo Lysis of Leukemic Blasts in a CD1d-Dependent Manner

Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative treatment option for hematologic malignancies but relapse remains the most common cause of death. Infusion of donor lymphocytes (DLIs) can induce remission and prolong survival by exerting graft-vs.-leukemia (GVL) effects. However, sufficient tumor control cannot be established in all patients and occurrence of graft-vs.-host disease (GVHD) prevents further dose escalation. Previous data indicate that invariant natural killer T (iNKT) cells promote anti-tumor immunity without exacerbating GVHD. In the present study we investigated lysis of leukemic blasts through iNKT cells from donor-derived lymphocytes for leukemia control and found that iNKT cells constitute about 0.12% of cryopreserved donor T cells. Therefore, we established a 2-week cell culture protocol allowing for a robust expansion of iNKT cells from cryopreserved DLIs (DLI-iNKTs) that can be used for further preclinical and clinical applications. Such DLI-iNKTs efficiently lysed leukemia cell lines and primary patient AML blasts ex vivo in a dose- and CD1d-dependent manner. Furthermore, expression of CD1d on target cells was required to release proinflammatory cytokines and proapoptotic effector molecules. Our results suggest that iNKT cells from donor-derived lymphocytes are involved in anti-tumor immunity after allo-HCT and therefore may reduce the risk of relapse and improve progression-free and overall survival.

G-CSF administration prior to donor lymphocyte apheresis promotes anti-leukaemic effects in allogeneic HCT patients

Donor lymphocyte infusion (DLI) is an effective method to establish full donor chimerism or to prevent and treat relapse after allogeneic haematopoietic cell transplantation (allo-HCT). Usually, DLIs are collected from naïve donors as steady-state lymphocytes. When donor lymphocytes are collected during stem cell apheresis, donors are pre-treated with granulocyte colony-stimulating factor (G-CSF). However, the impact of G-CSF stimulation and the resulting composition of DLIs on beneficial anti-leukaemic responses and survival remain elusive. Therefore, we performed a retrospective analysis to evaluate the role of G-CSF-DLIs: 44 patients received either steady-state DLIs or G-CSF-DLIs to prevent and treat relapse or establish full donor chimerism after allo-HCT. The G-CSF-DLI patient cohort showed an improved conversion to full donor chimerism and a lower cumulative incidence of relapse or disease progression without a significantly increased cumulative incidence of graft-versus-host disease (GVHD). CD34⁺ cells, monocytic myeloid-derived suppressor cells and monocytes as well as donor age and the subsequent occurrence of chronic GVHD were identified as risk factors that significantly improve overall survival after DLI administration. In conclusion, our data suggest that administration of G-CSF-DLIs results in graft-versus-leukaemia effects without exacerbating GVHD, therefore, improving survival after DLIs.

Culture-Expanded Human Invariant Natural Killer T Cells Suppress T-Cell Alloreactivity and Eradicate Leukemia

Graft-versus-host disease (GVHD) is a major cause of significant morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Invariant natural killer T (iNKT) cells are potent regulators of immune responses, protect from lethal GVHD, and promote graft-versus-leukemia effects in murine studies. Since iNKT cells constitute less than 0.5% of human peripheral blood mononuclear cells (PBMCs), in vitro expansion with their glycolipid ligands is required before they can be used for cytotherapy and experimental purposes. Three weeks of cell culture and autologous restimulation with either KRN7000, PBS44, or PBS57 resulted in a robust proliferation of iNKT cells from human PBMCs. Next, iNKT cells were sorted to a purity higher than 90% being crucial for further experimental and clinical applications. These iNKT cells significantly decreased activation and proliferation of allogeneic CD3+ T lymphocytes. In addition, leukemia cell lines and primary leukemia cells were efficiently lysed by culture-expanded iNKT cells. Importantly, culture-expanded donor iNKT cells promoted robust antileukemia activity against HLA-matched allogeneic patient leukemia cells. Our data indicate that the adoptive transfer of culture-expanded iNKT cells could be a powerful cytotherapeutic approach to induce immune tolerance and prevent leukemia relapse after allogeneic HCT in humans.

Accuracy of body mass index-defined overweight in fire fighters

BACKGROUND

Overweight, obesity and weight gain are significant problems in the U.S. fire service. While classification of obesity using body mass index (BMI) has demonstrated accuracy and low rates of false positives when compared with body fat percentage (BF%)-based standards, no studies have examined the accuracy of BMI-based overweight and normal weight status with other comparable body composition indices.

AIMS

To compare overweight and normal weight BMI categories with BF% standards from the American Council on Exercise and analogous waist circumference (WC) categories and to examine rates and types of misclassification in fire fighters.

METHODS

Data were collected from 11 randomly selected career fire departments in the International Association of Fire Chief's Missouri Valley Region. Demographics, occupational history, and body composition indices (weight, BF% and WC) were obtained from male career fire fighters who were categorized as normal weight or overweight based on BMI.

RESULTS

There were 293 participants of whom 92 had normal BMI. There were low rates of false positives (12%) and moderate rates of false negatives (22%) when comparing BMI categories to the compar able BF% categories. However, using WC as the standard resulted in very high rates of false positives (63%) and very low rates of false negatives (5%).

CONCLUSIONS

BMI-based overweight status was associated with significant errors in classification depending on the standard to which it was compared.

Vertical gradient in soil temperature stimulates development and increases biomass accumulation in barley

We have detailed knowledge from controlled environment studies on the influence of root temperature on plant performance, growth and morphology. However, in all studies root temperature was kept spatially uniform, which motivated us to test whether a vertical gradient in soil temperature affected development and biomass production. Roots of barley seedlings were exposed to three uniform temperature treatments (10, 15 or 20°C) or to a vertical gradient (20-10°C from top to bottom). Substantial differences in plant performance, biomass production and root architecture occurred in the 30-day-old plants. Shoot and root biomass of plants exposed to vertical temperature gradient increased by 144 respectively, 297%, compared with plants grown at uniform root temperature of 20°C. Additionally the root system was concentrated in the upper 10cm of the soil substrate (98% of total root biomass) in contrast to plants grown at uniform soil temperature of 20°C (86% of total root biomass). N and C concentrations in plant roots grown in the gradient were significantly lower than under uniform growth conditions. These results are important for the transferability of 'normal' greenhouse experiments where generally soil temperature is not controlled or monitored and open a new path to better understand and experimentally assess root-shoot interactions.

Gap-filling methods for 3D PlanTIS data

The range of positron emitters and their labeled compounds have led to high-resolution PET scanners becoming widely used, not only in clinical and pre-clinical studies but also in plant studies. A high-resolution PET scanner, plant tomographic imaging system (PlanTIS), was designed to study metabolic and physiological functions of plants noninvasively. The gantry of the PlanTIS scanner has detector-free regions. Even when the gantry of the PlanTIS is rotated during the scan, these regions result in missing sinogram bins in the acquired data. Missing data need to be estimated prior to the analytical image reconstructions in order to avoid artifacts in the final reconstructed images. In this study, we propose three gap-filling methods for estimation of the unique gaps existing in the 3D PlanTIS sinogram data. The 3D sinogram data were gap-filled either by linear interpolation in the transaxial planes or by the bicubic interpolation method (proposed for the ECAT high-resolution research tomograph) in the transradial planes or by the inpainting method in the transangular planes. Each gap-filling method independently compensates for slices in one of three orthogonal sinogram planes (transaxial, transradial and transangular planes). A 3D numerical Shepp-Logan phantom and the NEMA image quality phantom were used to evaluate the methods. The gap-filled sinograms were reconstructed using the analytical 3D reprojection (3DRP) method. The NEMA phantom sinograms were also reconstructed by the iterative reconstruction method, ordered subsets maximum a posteriori one step late (OSMAPOSL), to compare the results of gap filling followed by 3DRP with the results of OSMAPOSL reconstruction without gap filling. The three methods were evaluated quantitatively (by mean square error and coefficients of variation) over the selected regions of the 3D numerical Shepp-Logan phantom at eight different Poisson noise levels. Moreover, the NEMA phantom scan data were used in visual assessments of the methods. We observed that all methods improved the reconstructed images both quantitatively and visually. Therefore, the proposed gap-filling methods followed by the analytical 3DRP are alternative for the reconstructions of not only the 3D PlanTIS data, but also other PET scanner data of the ClearPET family.

Design and initial performance of PlanTIS: a high-resolution positron emission tomograph for plants

Positron emitters such as (11)C, (13)N and (18)F and their labelled compounds are widely used in clinical diagnosis and animal studies, but can also be used to study metabolic and physiological functions in plants dynamically and in vivo. A very particular tracer molecule is (11)CO(2) since it can be applied to a leaf as a gas. We have developed a Plant Tomographic Imaging System (PlanTIS), a high-resolution PET scanner for plant studies. Detectors, front-end electronics and data acquisition architecture of the scanner are based on the ClearPET system. The detectors consist of LSO and LuYAP crystals in phoswich configuration which are coupled to position-sensitive photomultiplier tubes. Signals are continuously sampled by free running ADCs, and data are stored in a list mode format. The detectors are arranged in a horizontal plane to allow the plants to be measured in the natural upright position. Two groups of four detector modules stand face-to-face and rotate around the field-of-view. This special system geometry requires dedicated image reconstruction and normalization procedures. We present the initial performance of the detector system and first phantom and plant measurements.

Distribution of photoassimilates in the pea plant: chronology of events in non-fertilized ovaries and effects of gibberellic acid

The short-lived isotope(11)C (t1/2=20.4 min) has been used to study assimilate distribution in intact pea plants (Pisum sativum L.). Radiolabel was measured at the leaf fed with(11)CO2 (feed-leaf), at the ovary of the flower subtended by this leaf, and in shoot apex and roots of individual plants. Considerable(11)C-radiolabel was detected in the young ovaries during the first days after anthesis. Thereafter, when the ovaries stopped growing the uptake of(11)C rapidly decreased. At this developmental stage only apex and roots were competing for the photoassimilates. Fertilization, however, restored the strong sink activity of the ovaries. The same effect could be achieved by applying gibberellic acid to non-fertilized ovaries. About 2 h after treatment the residual(11)C-radiolabel entering the ovary started to increase and, at about the same time, the ovary resumed growth. Feed-leaf photosynthesis, as well as export of(11)C-radiolabel out of the leaf, was not changed by the treatment. The(11)C experiments show the dynamic behaviour of the sinks during developmental stages from the day of anthesis until 5 d later and demonstrate that phytohormones may play an important role in regulating carbon distribution.

Translocation profiles of (11)C-assimilates in the petiole of Marsilea quadrifolia L

An array of three multipliers with BGO-crystals arranged along the petiole has been used to study the movement of (11)C-assimilate in Marsilea quadrifolia L. The leaf blades were exposed to a 3-6 min pulse of (11)CO2 under continuous light. Data were recorded with 10-s counting intervals and corrected for background, sensitivity of detectors, and (11)C-decay. The speed of translocation could be obtained from the time difference between the straight lines of (11)C-increase monitored at different positions along the petiole. The speed was within the range of 60 to 150 cm h(-1). Cutting as well as cold treatment at definite locations on the petiole led to an immediate stop of (11)C-movement. Both inhibition and-in the case of chilling-restoration of translocation were detectable within minutes. When the assimilation chamber was flushed with nitrogen gas, the normal increase of (11)C at the monitored sites slowed down which, after prolonged N2-treatment, even resulted in a decrease. With a time-delay down the petiole, replacement of N2 by an air-stream led to complete restoration of the (11)C-slope. These and similar shortterm effects on translocation could not be detected by former methods. This technique is also useful in with species other than Marsilea qu., which was chosen as a test plant because of the anatomical 'simplicity' of its petiole.