Exploiting the Role of Endogenous Lymphoid-Resident Dendritic Cells in the Priming of NKT Cells and CD8+ T Cells to Dendritic Cell-Based Vaccines

Transfer of antigen between antigen-presenting cells (APCs) is potentially a physiologically relevant mechanism to spread antigen to cells with specialized stimulatory functions. Here we show that specific CD8+ T cell responses induced in response to intravenous administration of antigen-loaded bone marrow-derived dendritic cells (BM-DCs), were ablated in mice selectively depleted of endogenous lymphoid-resident langerin+ CD8α+ dendritic cells (DCs), suggesting that the antigen is transferred from the injected cells to resident APCs. In contrast, antigen-specific CD4+ T cells were primed predominantly by the injected BM-DCs, with only very weak contribution of resident APCs. Crucially, resident langerin+ CD8α+ DCs only contributed to the priming of CD8+ T cells in the presence of maturation stimuli such as intravenous injection of TLR ligands, or by loading the BM-DCs with the glycolipid α-galactosylceramide (α-GalCer) to recruit the adjuvant activity of activated invariant natural killer-like T (iNKT) cells. In fact, injection of α-GalCer-loaded CD1d−/− BM-DCs resulted in potent iNKT cell activation, suggesting that this glycolipid antigen can also be transferred to resident CD1d+ APCs. While iNKT cell activation per se was independent of langerin+ CD8α+ DCs, some iNKT cell-mediated activities were reduced, notably release of IL-12p70 and transactivation of NK cells. We conclude that both protein and glycolipid antigens can be exchanged between distinct DC species. These data suggest that the efficacy of DC-based vaccination strategies may be improved by the incorporation of a systemic maturation signal aimed to engage resident APCs in CD8+ T cell priming, and α-GalCer may be particularly well suited to this purpose

Increasing the potency of dendritic cell based vaccines for the treatment of cancer

Tumours can be eradicated by T cells that recognise unique tumour-associated antigens. These T cells are initially stimulated by dendritic cells (DCs) that have acquired antigens from tumour tissue. Vaccination strategies that increase the frequencies of tumour-specific T cells by enhancing the activity of DCs are being evaluated in the clinic as novel cancer therapies. Our hypothesis is that existing DC-based vaccination strategies can be improved by stimulating toll-like receptor (TLR) signalling in the DCs, and also by encouraging interactions with iNKT cells, as these two activities are known to enhance DC function. It was also hypothesised that superior T cell responses could be induced by combining these two activities together. We used the TLR 4 agonist monophosphoryl lipid A (MPL) alone and in combination with other TLR agonists to achieve effective activation of bone marrow-derived DCs (BM-DCs) cultured in-vitro, which was characterised by upregulated expression of maturation markers on the cell surface, and enhanced release of pro-inflammatory cytokines. Some TLR agonist combinations provided significantly enhanced activities in this regard, notably the combination of MPL with either the TLR 2 agonist Pam3Cys, or the TLR 7/8 agonist Resiquimod. Although in-vitro activated BM-DCs were unable to induce stronger antigen-specific CD8+ T cell responses after intravenous injection when compared to BMDCs without TLR stimulation, enhanced CD8+ T cell responses were achieved in-vivo with the co-administration of TLR ligands, implying that TLR stimulation needed to act on cells of the host. Further studies identified the langerin-expressing CD8ɑ+ splenic DC subset in the spleen as recipients of antigen that was transferred from injected cells, and that these recipients were participants in the cross-presentation and T cell priming activities driving the CD8+ T cell response after vaccination. Antigen-loaded BM-DCs carrying the NKT cell ligand ɑ-galactosylceramide (ɑ-GalCer) were found to consistently increase antigen-specific CD8+ T cell responses in-vivo, and also cytotoxic responses as seen in cytotoxic killing assays. Again, langerin-expressing CD8ɑ+ splenic DCs were shown to be involved in this response by acquiring antigen and ɑ-GalCer from the injected vaccine BM-DCs. Finally, it was possible to achieve even greater CD8+ T cell responses in-vivo by injecting BM-DCs carrying antigen and ɑ-GalCer, together with timely co-administration of the TLR agonist. These results suggest a reassessment of the activities of DC-based vaccines to include the important role of “courier” to DCs already resident in the host that can be exploited to improve vaccination outcomes

Facilitators and barriers for implementation of health programmes with Māori communities

Abstract Background Addressing health inequities that Māori (Indigenous peoples) communities face in New Zealand is a key aim of researchers and practitioners. However, there is limited understanding of the implementation processes and outcomes of health programmes for addressing these inequities. The aim of this study was twofold: (a) to identify correlates of implementation outcomes and (b) to identify facilitators and barriers to implementation effectiveness. Methods The study involved a concurrent mixed method approach. Through an online survey, 79 participants with experience in implementing a health programme with a Māori community identified outcomes and processes of the programme. Additionally, nine Māori community providers shared their perceptions and experience of facilitators and barriers to implementation effectiveness through an in-depth interview. The quantitative and qualitative findings were integrated to address the aims of the study. Results For the first aim, we identified two key outcomes: overall health impacts and sustainability. Three of the variables had significant and positive bivariate correlations with health impacts: cultural alignment, community engagement, and individual skills. The only significant correlate of sustainability was evidence-based. For the second aim, participants described four facilitators (leadership, whanaungatanga [relationships], sharing information, digestible information) and four barriers (system constraints, lack of funding, cultural constraints, lack of engagement) to effective implementation. Conclusion Overall, leadership, aligning culture, and building on whanaungatanga, while getting financial resources and systems support, are the core elements to supporting implementation efforts in Māori communities

Grading of clear cell renal cell carcinoma should be based on nucleolar prominence

Fuhrman grading of renal cell carcinoma focuses on features of nuclear size, nuclear shape, and nucleolar prominence. Despite the reported widespread usage of Fuhrman grading in clinical studies, there is debate as to the prognostic significance and reproducibility of its criteria. It has been noted that many pathologists rely on assessment of nucleolar prominence alone when grading renal cell carcinoma; however, the validity of this remains unconfirmed. This study was undertaken to determine the relationship of the 3 morphologic components of the Fuhrman grading system with one another and to determine which, if any of these, can be correlated with outcome for clear cell renal cell carcinoma. One hundred twenty-one organ-confined clear cell renal cell carcinomas were examined in this study. Parameters of nuclear size (area, major axis, perimeter) and nuclear shape (shape factor, nuclear compactness) were assessed by image analysis, whereas nucleolar prominence was assigned (grades 1 to 3) using the criteria of Fuhrman. On the basis of the predominant grade present, there were 17 nucleolar grade 1, 90 nucleolar grade 2, and 14 nucleolar grade 3 tumors. When the high-power field in each tumor with the worst nucleolar grade was assessed, there was 1 nucleolar grade 1, 68 nucleolar grade 2, and 52 nucleolar grade 3 tumors. Predominant and worst nucleolar grade correlated with all measures of nuclear size, but not nuclear shape. Worst nucleolar grade and all parameters of nuclear size were significantly associated with outcome. On multivariate analysis, worst nucleolar grade retained a significant association with survival when modeled with nuclear area. Neither worst nucleolar grade nor major nuclear axis/nuclear perimeter was significantly associated with survival when modeled together. In this study, we have shown that worst nucleolar grade and nuclear size are of prognostic significance for clear cell renal cell carcinoma. We have further shown the association of worst nucleolar grade with outcome to be independent of nuclear area, whereas it is a dependent variable when tested against other parameters of nuclear size. These findings indicate that worst nucleolar grading alone is a valid grading parameter for clear cell renal cell carcinoma. Copyrigh

A worldwide population of Streptococcus pyogenes strains circulating among school-aged children in Auckland, New Zealand: a genomic epidemiology analysisResearch in context

Summary: Background: Acute rheumatic fever (ARF) is a serious post-infectious sequala of Group A Streptococcus (GAS, Streptococcus pyogenes). In New Zealand (NZ) ARF is a major cause of health inequity. This study describes the genomic analysis of GAS isolates associated with childhood skin and throat infections in Auckland NZ. Methods: Isolates (n = 469) collected between March 2018 and October 2019 from the throats and skin of children (5–14 years) underwent whole genomic sequencing. Equal representation across three ethnic groups was ensured through sample quotas with isolates obtained from Indigenous Māori (n = 157, 33%), NZ European/Other (n = 149, 32%) and Pacific Peoples children (n = 163, 35%). Using in silico techniques isolates were classified, assessed for diversity, and examined for distribution differences between groups. Comparisons were also made with GAS strains identified globally. Findings: Genomic analysis revealed a diverse population consisting of 65 distinct sequence clusters. These sequence clusters spanned 49 emm-types, with 11 emm-types comprised of several, distinct sequence clusters. There is evidence of multiple global introductions of different lineages into the population, as well as local clonal expansion. The M1UK lineage comprised 35% of all emm1 isolates. Interpretation: The GAS population was characterized by a high diversity of strains, resembling patterns observed in low- and middle-income countries. However, strains associated with outbreaks and antimicrobial resistance commonly found in high-income countries were also observed. This unique combination poses challenges for vaccine development, disease management and control. Funding: The work was supported by the Health Research Council of New Zealand (HRC), award number 16/005