Diaci v3.0: chromosome-level assembly, de novo transcriptome, and manual annotation of Diaphorina citri, insect vector of Huanglongbing.

Background: Diaphorina citri is an insect vector of "Candidatus Liberibacter asiaticus" (CLas), the gram-negative bacterial pathogen associated with citrus greening disease. Control measures rely on pesticides with negative impacts on the environment, natural ecosystems, and human and animal health. In contrast, gene-targeting methods have the potential to specifically target the vector species and/or reduce pathogen transmission.

Protective Role of NS1-Specific Antibodies in the Immune Response to Dengue Virus Through Antibody-Dependent Cellular Cytotoxicity.

Background: Dengue virus (DENV) nonstructural protein 1 (NS1) has multiple functions within infected cells, on the cell surface, and in secreted form, and is highly immunogenic. Immunity from previous DENV infections is known to exert both positive and negative effects on subsequent DENV infections, but the contribution of NS1-specific antibodies to these effects is incompletely understood.

Methods: We investigated the functions of NS1-specific antibodies and their significance in DENV infection.

Annotation of glycolysis, gluconeogenesis, and trehaloneogenesis pathways provide insight into carbohydrate metabolism in the Asian citrus psyllid.

Citrus greening disease is caused by the pathogen Liberibacter asiaticus and transmitted by the Asian citrus psyllid, . No curative treatment or significant prevention mechanism exists for this disease, which causes economic losses from reduced citrus production. A high-quality genome of is being manually annotated to provide accurate gene models to identify novel control targets and increase understanding of this pest.

Longitudinal Analysis of Dengue Virus-Specific Memory T Cell Responses and Their Association With Clinical Outcome in Subsequent DENV Infection.

Memory T cells resulting from primary dengue virus (DENV) infection are hypothesized to influence the clinical outcome of subsequent DENV infection. However, the few studies involving prospectively collected blood samples have found weak and inconsistent associations with outcome and variable temporal trends in DENV-specific memory T cell responses between subjects. This study used both and cultured ELISPOT assays to further evaluate the associations between DENV serotype-cross-reactive memory T cells and severity of secondary infection.

Non-structural protein 1-specific antibodies directed against Zika virus in humans mediate antibody-dependent cellular cytotoxicity.

There is growing interest in understanding antibody (Ab) function beyond neutralization. The non-structural protein 1 (NS1) of Zika virus (ZIKV) is an attractive candidate for an effective vaccine as Abs against NS1, unlike the envelope or premembrane, do not carry the risk of mediating antibody-dependent enhancement. Our aim was to evaluate whether ZIKV NS1 Abs elicited following natural infection in humans can mediate antibody-dependent cellular cytotoxicity (ADCC).

T lymphocyte responses to flaviviruses - diverse cell populations affect tendency toward protection and disease.

Dengue virus (DENV), Yellow Fever virus, West Nile virus, Japanese encephalitis virus and Zika virus are medically important flaviviruses transmitted to humans by mosquitoes and circulate in overlapping geographic areas. Cross-reactive immune responses have been demonstrated among the flaviviruses, particularly the four DENV serotypes. The immunological imprint left by a flavivirus infection can therefore have profound effects on the responses to subsequent infections.

Transcriptional and clonal characterization of B cell plasmablast diversity following primary and secondary natural DENV infection.

Antibody-mediated humoral immunity is thought to play a central role in mediating the immunopathogenesis of acute DENV infection, but limited data are available on the diversity, specificity, and functionality of the antibody response at the molecular level elicited by primary or secondary DENV infection. In order to close this functional gap in our understanding of DENV-specific humoral immunity, we utilized high-throughput single cell RNA sequencing to investigate B cells circulating in both primary and secondary natural DENV infections. We captured full-length paired immunoglobulin receptor sequence data from 9,027 B cells from a total of 6 subjects, including 2,717 plasmablasts.

Vaccine innovations for emerging infectious diseases-a symposium report.

Vaccines have been incredibly successful at stemming the morbidity and mortality of infectious diseases worldwide. However, there are still no effective vaccines for many serious and potentially preventable infectious diseases. Advances in vaccine technology, including new delivery methods and adjuvants, as well as progress in systems biology and an increased understanding of the human immune system, hold the potential to address these issues.

Longitudinal Analysis of Memory B and T Cell Responses to Dengue Virus in a 5-Year Prospective Cohort Study in Thailand.

Prior exposure to dengue virus (DENV) has a profound impact on the outcome of infection, which varies according to the interval between infections. Antibodies secreted by B cells and cytokines secreted by T cells are thought to contribute both to protective immunity against DENV and the pathogenesis of dengue disease. We analyzed peripheral blood mononuclear cells (PBMC) collected from Thai children over a 5-year prospective cohort study to define the dynamics of DENV-specific memory B and T cell responses and the impact of symptomatic or subclinical DENV infections.

Peripheral follicular helper T cells in acute viral diseases: a perspective on dengue.

Follicular helper T cells (T) are a predominant subset of CD4 T cells specialized in providing help to B cells in germinal centers and necessary to generate T cell-dependent antibody responses. Peripheral T (pT) are the counterpart of T found in the circulation, which resemble T in many aspects of their phenotype and function. The CD4 pT subset has received a lot of interest recently because they are easy to access and have the potential to serve as a biomarker for long-lasting humoral immunity.

Protective versus pathologic pre-exposure cytokine profiles in dengue virus infection.

Background: Hyperendemic circulation of all four types of dengue virus (DENV-1-4) has expanded globally, fueling concern for increased incidence of severe dengue. While the majority of DENV infections are subclinical, epidemiologic studies suggest that type-cross-reactive immunity can influence disease outcome in subsequent infections. The mechanisms controlling these differential clinical outcomes remain poorly defined.

Multiplexed FluoroSpot for the Analysis of Dengue Virus- and Zika Virus-Specific and Cross-Reactive Memory B Cells.

Dengue virus (DENV) and Zika virus (ZIKV) are mosquito-borne pathogens that have a significant impact on human health. Immune sera, mAbs, and memory B cells (MBCs) isolated from patients infected with one DENV type can be cross-reactive with the other three DENV serotypes and even more distantly related flaviviruses such as ZIKV. Conventional ELISPOTs effectively measure Ab-secreting B cells but because they are limited to the assessment of a single Ag at a time, it is challenging to distinguish serotype-specific and cross-reactive MBCs in the same well.

Upregulation of HLA-E by dengue and not Zika viruses.

Introduction: The most severe form of dengue virus (DENV) illness, dengue haemorrhagic fever, is characterised by plasma leakage and increased vascular permeability.

Objectives: Given the critical role that endothelial cells play in the pathogenesis of DENV, we wanted to determine whether infection with DENV altered the expression of MHC class I related genes including HLA-E.

Results: In this study, we provide evidence that HLA-E but not MICA/B or HLA-G is upregulated by all four serotypes of DENV in an endothelial cell line human microvascular endothelial cells (HMEC)-1.

Activation of Peripheral T Follicular Helper Cells During Acute Dengue Virus Infection.

Background: Follicular helper T cells (TFH) are specialized CD4 T cells required for B-cell help and antibody production.

Methods: Given the postulated role of immune activation in dengue disease, we measured the expansion and activation of TFH in the circulation (peripheral TFH [pTFH]) collected from Thai children with laboratory-confirmed acute dengue virus (DENV) infection.

Results: We found significant expansion and activation of pTFH subsets during acute infection with the highest frequencies of activated pTFH (PD1hi pTFH and PD1+CD38+ pTFH) detected during the critical phase of illness.

Regulation and Function of NK and T Cells During Dengue Virus Infection and Vaccination.

The focus of this review is to discuss findings in the last 10 years that have advanced our understanding of human NK cell responses to dengue virus. We will review recently identified interactions of activating and inhibitory receptors on NK cells with dengue virus, human NK responses to natural dengue infection and highlight possible interactions by which NK cells may shape adaptive immune responses. T cell responses to natural dengue infection will be reviewed by Laura Rivino in Chap.

Defining the role of NK cells during dengue virus infection.

In recent years, our understanding of the complex number of signals that need to be integrated between a diverse number of receptors present on natural killer (NK) cells and ligands present on target cells has improved. Here, we review the progress made in identifying interactions between dengue viral peptides presented on HLA Class 1 molecules with inhibitory and activating killer-like immunoglobulin receptors on NK cells, direct interactions of viral proteins with NK cell receptors, the involvement of dengue virus-specific antibodies in mediating antibody-dependent cell-mediated cytotoxicity and the role of soluble factors in modulating NK cell responses. We discuss findings of NK cell activation early after natural dengue infection, and point to the role that NK cells may play in regulating both innate and adaptive immune responses, in the context of our new appreciation of interactions of dengue virus with specific NK cell receptors.

Humanized mouse models to study human cell-mediated and humoral responses to dengue virus.

Several candidate dengue virus vaccines are in clinical trials and show promise as an effective measure to control dengue. However, it is becoming clear that additional vaccine candidates may be needed as there is concern about the durability of the immune response to all four serotypes of vaccine components and efficacy varies dependent on the immune status of the individual. The lack of an appropriate animal model to mimic human dengue has deterred the development of vaccines and anti-viral therapies to dengue virus.

Detection, phenotyping and quantification of dengue virus-specific B cells using fluorescent probes.

Dengue viruses are some of the most important mosquito-borne pathogens worldwide. They cause illness in 50-100 million individuals per year and have a significant global health impact in low- and middle-income countries. It is important to improve our understanding of the humoral response to dengue virus, as antibodies (Abs) are associated with protection from or susceptibility to severe dengue disease.

Immune-mediated cytokine storm and its role in severe dengue.

Dengue remains one of the most important mosquito-borne diseases worldwide. Infection with one of the serologically related dengue viruses (DENVs) can lead to a wide range of clinical manifestations and severity. Severe dengue is characterized by plasma leakage and abnormal bleeding that can lead to shock and death.

Improved B cell development in humanized NOD mice transgenically expressing human stem cell factor, granulocyte-macrophage colony-stimulating factor and interleukin-3.

Introduction: Immunodeficient mice engrafted with human immune systems support studies of human hematopoiesis and the immune response to human-specific pathogens. A significant limitation of these humanized mouse models is, however, a severely restricted ability of human B cells to undergo class switching and produce antigen-specific IgG after infection or immunization.

Methods: In this study, we have characterized the development and function of human B cells in NOD- (NSG) mice transgenically expressing human stem cell factor (SCF), granulocyte macrophage colony-stimulating factor (GM-CSF), and IL-3 (NSG-SGM3) following engraftment with human hematopoietic stem cells, autologous fetal liver, and thymic tissues (bone marrow, liver, thymus or BLT model).

Dynamics of Dengue Virus (DENV)-Specific B Cells in the Response to DENV Serotype 1 Infections, Using Flow Cytometry With Labeled Virions.

Background: The development of reagents to identify and characterize antigen-specific B cells has been challenging.

Methods: We recently developed Alexa Fluor-labeled dengue viruses (AF DENVs) to characterize antigen-specific B cells in the peripheral blood of DENV-immune individuals.

Results: In this study, we used AF DENV serotype 1 (AF DENV-1) together with AF DENV-2 on peripheral blood mononuclear cells (PBMCs) from children in Thailand with acute primary or secondary DENV-1 infections to analyze the phenotypes of antigen-specific B cells that reflected their exposure or clinical diagnosis.

CpG Improves Influenza Vaccine Efficacy in Young Adult but Not Aged Mice.

Several studies have shown a reduced efficacy of influenza vaccines in the elderly compared to young adults. In this study, we evaluated the immunogenicity and protective efficacy of a commercially available inactivated influenza vaccine (Fluzone®) in young adult and aged mice. C57/BL6 mice were administered a single or double immunization of Fluzone® with or without CpG and challenged intranasally with H1N1 A/California/09 virus.

Analysis of cell-mediated immune responses in support of dengue vaccine development efforts.

Dengue vaccine development has made significant strides, but a better understanding of how vaccine-induced immune responses correlate with vaccine efficacy can greatly accelerate development, testing, and deployment as well as ameliorate potential risks and safety concerns. Advances in basic immunology knowledge and techniques have already improved our understanding of cell-mediated immunity of natural dengue virus infection and vaccination. We conclude that the evidence base is adequate to argue for inclusion of assessments of cell-mediated immunity as part of clinical trials of dengue vaccines, although further research to identify useful correlates of protective immunity is needed.

Fluorescently labeled dengue viruses as probes to identify antigen-specific memory B cells by multiparametric flow cytometry.

Low frequencies of memory B cells in the peripheral blood make it challenging to measure the functional and phenotypic characteristics of this antigen experienced subset of B cells without in vitro culture. To date, reagents are lacking to measure ex vivo frequencies of dengue virus (DENV)-specific memory B cells. We wanted to explore the possibility of using fluorescently labeled DENV as probes to detect antigen-specific memory B cells in the peripheral blood of DENV immune individuals.

Dengue virus infection induces broadly cross-reactive human IgM antibodies that recognize intact virions in humanized BLT-NSG mice.

The development of small animal models that elicit human immune responses to dengue virus (DENV) is important since prior immunity is a major risk factor for developing severe dengue disease. This study evaluated anti-DENV human antibody (hAb) responses generated from immortalized B cells after DENV-2 infection in NOD-scid IL2rγ(null) mice that were co-transplanted with human fetal thymus and liver tissues (BLT-NSG mice). DENV-specific human antibodies predominantly of the IgM isotype were isolated during acute infection and in convalescence.