31 research outputs found

    Local Seed Business in the Context of Integrated Seed Sector Development

    Get PDF
    Quality seed is a key input for agriculture, with a direct impact on agricultural production and productivity. Integrated seed sector development (ISSD) is an inclusive approach that recognizes and builds upon a diversity of seed systems in the sector. We use the ISSD approach to guide us in the design and implementation of seed sector interventions that are complementary to farmersā€™practices, with the main aim of increasing farmersā€™ access to quality seed of superior varieties. In working with the ISSD approach, we recognize a number of guiding principles. In this paper, we describe these principles, and provide examples of how we work with the system of local seed business (LSB) in the ISSD programs in Ethiopia and Uganda. We recognize that LSBs offer an important service to communities by providing access to quality seed of crops and varieties that cannot be obtained reliably through other sources. The guiding principles help us to work towards the development of sustainable LSBs. Within the context of ISSD Africa we will continue to investigate and design interventions to address challenges in seed sector development, focusing on aselect number of themes that are relevant to the LSB context

    HLA monomers as a tool to monitor indirect allorecognition

    Get PDF
    BACKGROUND: Recognition of donor antigens can occur through two separate pathways: the direct pathway (non-self HLA on donor cells) and the indirect pathway (self-restricted presentation of donor derived peptides on recipient cells). Indirect allorecognition is important in the development of humoral rejection; therefore, there is an increasing interest in the monitoring of indirect alloreactive T-cells. We have used an in vitro model to determine the optimal requirements for indirect presentation and assessed the risk for semidirect presentation in this system. METHODS: HLA-typed monocyte-derived dendritic cells (moDCs) were incubated with cellular fragments or necrotic cells and incubated with either indirect or direct alloreactive T-cell clones. T-cell reactivity was measured through proliferation or cytokine secretion. HLA-typed moDC, monocytes, or PBMCs were incubated with HLA class I monomers, in combination with either direct/indirect T-cell clones. RESULTS: Although both were efficiently taken up, alloreactivity was limited to the semi-direct pathway, as measured by allospecific CD4 (indirect) and CD8 T-cell clones (direct) when cells were used. In contrast, HLA-A2 monomers were not only efficiently taken up but also processed and presented by HLA-typed moDC, monocytes, and PBMCs. Activation was shown by a dose-dependent induction of IFN-Ī³ production and proliferation by the CD4 T-cell clone. Antigen presentation was most efficient when the monomers were cultured for longer periods (24-48 hr) in the presence of the T-cells. Using this method, no reactivity was observed by the CD8 T-cell clone, confirming no semidirect alloreactivity. CONCLUSION: We have developed a system that could be used to monitor indirect alloreactive T-cells.Stemcel biology/Regenerative medicine (incl. bloodtransfusion

    Comparing CAR and TCR engineered T cell performance as a function of tumor cell exposure

    Get PDF
    Chimeric antigen receptor (CAR) T cell therapies have resulted in profound clinical responses in the treatment of CD19-positive hematological malignancies, but a significant proportion of patients do not respond or relapse eventually. As an alternative to CAR T cells, T cells can be engineered to express a tumor-targeting T cell receptor (TCR). Due to HLA restriction of TCRs, CARs have emerged as a preferred treatment moiety when targeting surface antigens, despite the fact that functional differences between engineered TCR (eTCR) T and CAR T cells remain ill-defined. Here, we compared the activity of CAR T cells versus engineered TCR T cells in targeting the B cell malignancy-associated antigen CD20 as a function of antigen exposure. We found CAR T cells to be more potent effector cells, producing higher levels of cytokines and killing more efficiently than eTCR T cells in a short time frame. However, we revealed that the increase of antigen exposure significantly impaired CAR T cell expansion, a phenotype defined by high expression of coinhibitory molecules and effector differentiation. In contrast, eTCR T cells expanded better than CAR T cells under high antigenic pressure, with lower expression of coinhibitory molecules and maintenance of an early differentiation phenotype, and comparable clearance of tumor cells.Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

    Safety of routine early MRI in preterm infants

    Get PDF
    Background: Cerebral MRI performed on preterm infants at term-equivalent 30 weeks' gestational age (GA) is increasingly performed as part of standard clinical care. Objective: We evaluated safety of these earlyMRI procedures. Materials and methods We retrospectively collected data on patient safety of preterm infants who underwent early MRI scans. Data were collected at fixed times before and after the MRI scan. MRI procedures were carried out according to a comprehensive guideline. Results: A total of 52 infants underwent an MRI scan at 30 weeks' GA. Although no serious adverse events occurred and vital parameters remained stable during the procedure, minor adverse events were encountered in 26 infants (50%). The MRI was terminated in three infants (5.8%) because of respiratory instability. Increased respiratory support within 24 h after the MRI was necessary for 12 infants (23.1%) and was significantly associated with GA, birth weight and the mode of respiratory support. Hypothermia (core temperature < 36Ā°C) occurred in nine infants (17.3%). Temperature dropped significantly after the MRI scan. Conclusion: Minor adverse events after MRI procedures at 30 weeks GA were common and should not be underestimated. A dedicated and comprehensive guideline for MRI procedures in preterm infants is essential

    Cutting edge: unconventional CD8+ T cell recognition of a naturally occurring HLA-A*02:01-restricted 20mer epitope

    Get PDF
    Unconventional HLA class I-restricted CD8+Ā T cell epitopes, longer than 10 aa, have been implicated to play a role in human immunity against viruses and cancer. T cell recognition of long peptides, centrally bulging from the HLA cleft, has been described previously. Alternatively, long peptides can contain a linear HLA-bound core peptide, with a N- or C-terminal peptide "tail" extending from the HLA peptide binding groove. The role of such a peptide "tail" in CD8+Ā T cell recognition remains unclear. In this study, we identified a 20mer peptide (FLPTPEELGLLGPPRPQVLA [FLP]) derived from the IL-27R subunit Ī± gene restricted to HLA-A*02:01, for which we solved the crystal structure and demonstrated a long C-terminal "tail" extension. FLP-specific T cell clones demonstrated various recognition modes, some T cells recognized the FLP core peptide, while for other T cells the peptide tail was essential for recognition. These results demonstrate a crucial role for a C-terminal peptide tail in immunogenicity. </p

    Broadly applicable TCR-based therapy for multiple myeloma targeting the immunoglobulin J chain

    Get PDF
    Background: The immunoglobulin J chain (Jchain) is highly expressed in the majority of multiple myeloma (MM), and Jchain-derived peptides presented in HLA molecules may be suitable antigens for T-cell therapy of MM. Methods: Using immunopeptidomics, we identified Jchain-derived epitopes presented by MM cells, and pHLA tetramer technology was used to isolate Jchain-specific T-cell clones. Results: We identified T cells specific for Jchain peptides presented in HLA-A1, -A24, -A3, and -A11 that recognized and lysed JCHAIN-positive MM cells. TCRs of the most promising T-cell clones were sequenced, cloned into retroviral vectors, and transferred to CD8 T cells. Jchain TCR T cells recognized target cells when JCHAIN and the appropriate HLA restriction alleles were expressed, while JCHAIN or HLA-negative cells, including healthy subsets, were not recognized. Patient-derived JCHAIN-positive MM samples were also lysed by Jchain TCR T cells. In a preclinical in vivo model for established MM, Jchain-A1, -A24, -A3, and -A11 TCR T cells strongly eradicated MM cells, which resulted in 100-fold lower tumor burden in Jchain TCR versus control-treated mice. Conclusions: We identified TCRs targeting Jchain-derived peptides presented in four common HLA alleles. All four TCRs demonstrated potent preclinical anti-myeloma activity, encouraging further preclinical testing and ultimately clinical development.Proteomic

    The prognostic value of the tumorā€“stroma ratio is most discriminative in patients with grade III or tripleā€negative breast cancer

    Get PDF
    The tumor-stroma ratio (TSR) was evaluated as a promising parameter for breast cancer prognostication in clinically relevant subgroups of patients. The TSR was assessed on hematoxylin and eosin stained tissue slides of 1794 breast cancer patients from the Nottingham City Hospital. An independent second cohort of 737 patients from the Netherlands Cancer Institute to Antoni van Leeuwenhoek was used for evaluation. In the Nottingham Breast Cancer series, the TSR was an independent prognostic parameter for recurrence-free survival (RFS) (HR 1.35, 95% CI 1.10 to 1.66, p = 0.004). The interaction term was statistically significant for grade and triple-negative status. Multivariate Cox regression analysis showed a more pronounced effect of the TSR for RFS in grade III tumors (HR 1.89, 95% CI 1.43 to 2.51, p < 0.001) and triple-negative tumors (HR 1.86, 95% CI 1.10 to 3.14, p = 0.020). Comparable hazard ratios and confidence intervals were observed for grade and triple-negative status in the ONCOPOOL study. The prognostic value of TSR was not modified by age, tumor size, histology, estrogen receptor status, progesterone receptor status, human epidermal growth factor receptor 2 status or lymph node status. In conclusion, patients with a stroma-high tumor had a worse prognosis compared to patients with a stroma- low tumor. The prognostic value of the TSR is most discriminative in grade III tumors and triple-negative tumors. The TSR was not modified by other clinically relevant parameters making it a potential factor to be included for improved risk stratification

    PRAME and CTCFL-reactive TCRs for the treatment of ovarian cancer

    Get PDF
    Recurrent disease emerges in the majority of patients with ovarian cancer (OVCA). Adoptive T-cell therapies with T-cell receptors (TCRs) targeting tumor-associated antigens (TAAs) are considered promising solutions for less-immunogenic 'cold' ovarian tumors. In order to treat a broader patient population, more TCRs targeting peptides derived from different TAAs binding in various HLA class I molecules are essential. By performing a differential gene expression analysis using mRNA-seq datasets, PRAME, CTCFL and CLDN6 were selected as strictly tumor-specific TAAs, with high expression in ovarian cancer and at least 20-fold lower expression in all healthy tissues of risk. In primary OVCA patient samples and cell lines we confirmed expression and identified naturally expressed TAA-derived peptides in the HLA class I ligandome. Subsequently, high-avidity T-cell clones recognizing these peptides were isolated from the allo-HLA T-cell repertoire of healthy individuals. Three PRAME TCRs and one CTCFL TCR of the most promising T-cell clones were sequenced, and transferred to CD8+ T cells. The PRAME TCR-T cells demonstrated potent and specific antitumor reactivity in vitro and in vivo. The CTCFL TCR-T cells efficiently recognized primary patient-derived OVCA cells, and OVCA cell lines treated with demethylating agent 5-aza-2 '-deoxycytidine (DAC). The identified PRAME and CTCFL TCRs are promising candidates for the treatment of patients with ovarian cancer, and are an essential addition to the currently used HLA-A*02:01 restricted PRAME TCRs. Our selection of differentially expressed genes, naturally expressed TAA peptides and potent TCRs can improve and broaden the use of T-cell therapies for patients with ovarian cancer or other PRAME or CTCFL expressing cancers.Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

    Breast cancer risk genes: association analysis in more than 113,000 women

    Get PDF
    BACKGROUNDGenetic testing for breast cancer susceptibility is widely used, but for many genes, evidence of an association with breast cancer is weak, underlying risk estimates are imprecise, and reliable subtype-specific risk estimates are lacking.METHODSWe used a panel of 34 putative susceptibility genes to perform sequencing on samples from 60,466 women with breast cancer and 53,461 controls. In separate analyses for protein-truncating variants and rare missense variants in these genes, we estimated odds ratios for breast cancer overall and tumor subtypes. We evaluated missense-variant associations according to domain and classification of pathogenicity.RESULTSProtein-truncating variants in 5 genes (ATM, BRCA1, BRCA2, CHEK2, and PALB2) were associated with a risk of breast cancer overall with a P value of less than 0.0001. Protein-truncating variants in 4 other genes (BARD1, RAD51C, RAD51D, and TP53) were associated with a risk of breast cancer overall with a P value of less than 0.05 and a Bayesian false-discovery probability of less than 0.05. For protein-truncating variants in 19 of the remaining 25 genes, the upper limit of the 95% confidence interval of the odds ratio for breast cancer overall was less than 2.0. For protein-truncating variants in ATM and CHEK2, odds ratios were higher for estrogen receptor (ER)-positive disease than for ER-negative disease; for protein-truncating variants in BARD1, BRCA1, BRCA2, PALB2, RAD51C, and RAD51D, odds ratios were higher for ER-negative disease than for ER-positive disease. Rare missense variants (in aggregate) in ATM, CHEK2, and TP53 were associated with a risk of breast cancer overall with a P value of less than 0.001. For BRCA1, BRCA2, and TP53, missense variants (in aggregate) that would be classified as pathogenic according to standard criteria were associated with a risk of breast cancer overall, with the risk being similar to that of protein-truncating variants.CONCLUSIONSThe results of this study define the genes that are most clinically useful for inclusion on panels for the prediction of breast cancer risk, as well as provide estimates of the risks associated with protein-truncating variants, to guide genetic counseling. (Funded by European Union Horizon 2020 programs and others.)Molecular tumour pathology - and tumour geneticsMTG1 - Moleculaire genetica en pathologie van borstkanke

    Traces Of Power 1969

    No full text
    In 1975, Helmers, Mokken, Plijter and Stokman conducted a reseach into the network of board interlocks among Dutch companies. They selected the largest production companies, financial companies and government agencies in the Netherlands for 1969. Their original database contains information about 64 production companies, 22 financial companies and government agencies. They used different selection criteria for these categories. The main sources for information about the production and financial companies are annual reports and for the government agencies they used the Staatsalmanak 1970. Based on the information in appendix B3 in the 1975 publication "Graven naar macht: op zoek naar de kern van de Nederlandse economie" by Helmers et al., Heemskerk reconstructed the original database. Appendix B3 contains only persons that occupy seats in at least two different companies. The reconstructed database contains information about 84 production and financial companies, and about 24 government agencies. The reconstructed database shows the names of 448 interlocking directors
    corecore