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

BACKGROUND: Dengue virus (DENV) non-structural 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. We analyzed plasma samples collected in a prospective cohort study prior to symptomatic or subclinical secondary DENV infection. We measured binding to purified recombinant NS1 protein and to NS1-expressing CEM cells, antibody-mediated NK cell activation by plate-bound NS1 protein, and antibody-dependent cellular cytotoxicity (ADCC) of NS1-expressing target cells. RESULTS: We found that antibody responses to NS1 were highly serotype-cross-reactive and that subjects who experienced subclinical DENV infection had significantly higher antibody responses to NS1 in pre-infection plasma than subjects who experienced symptomatic infection. We observed strong positive correlations between antibody binding and NK activation. CONCLUSIONS: These findings demonstrate the involvement of NS1-specific antibodies in ADCC and provide evidence for a protective effect of NS1-specific antibodies in secondary DENV infection.

Celiac disease seroprevalence in patients with infertility. A case-control study.

BACKGROUND: Although most patients with celiac disease (CD) have digestive manifestations, in some of them they may be of extraintestinal (atypical) nature, such as chronic anemia, ataxia, and fertility disorders. OBJECTIVE: To determine the prevalence of CD-related antibodies in Mexican women with fertility disorders. MATERIAL AND METHODS: Case-control study of women who attended evaluation for fertility disorders in a specialized center. h-tTG-IgA, gliadin IgA II and gliadin IgG II were quantified; titers > 30 IU were considered positive. RESULTS: One-hundred and seventy-one cases and 171 controls were included; 137 patients (80.1%) had infertility, and 34 (19.9%), sterility. Eight patients (4.6%, 95% CI = 2.3-8.9) had at least one positive marker for CD in comparison with one woman in the control group (0.5%, 95% CI = 0.01-3, p = 0.04, odds ratio = 8.3). Six of the eight patients had unexplained infertility. CONCLUSIONS: Up to 4.6% of women with infertility had at least one positive marker for CD. As in other parts of the world, screening for CD could be recommended in women with infertility, especially in those with unexplained infertility.

ANTECEDENTES: Aunque los pacientes con enfermedad celiaca (EC) tienen en su mayoría manifestaciones digestivas, algunos pueden presentarlas de índole extraintestinal (atípicas), como anemia crónica, ataxia y trastornos de la fertilidad. OBJETIVO: Determinar la prevalencia de anticuerpos relacionados con EC en mujeres mexicanas con trastornos de la fertilidad. MATERIAL Y MÉTODOS: Estudio de casos y controles de mujeres que acudieron a valoración por trastornos de la fertilidad en un centro especializado. Se cuantificó h-tTG IgA, gliadina IgA II y gliadina IgG II; los títulos > 30 UI fueron considerados como positivos. RESULTADOS: Se incluyeron 171 casos y 171 controles; 137 pacientes (80.1 %) tuvieron infertilidad y 34 (19.9 %), esterilidad. Ocho pacientes (4.6 %, IC 95 % = 2.3-8.9) tuvieron al menos un marcador positivo para EC comparadas con una mujer del grupo control (0.5 %, IC 95 % = 0.01-3, p = 0.04, razón de momios = 8.3). Seis de las ocho pacientes presentaron infertilidad inexplicable. CONCLUSIONES: Hasta 4.6 % de las mujeres con infertilidad presentó al menos un marcador positivo para EC. Al igual que en otras partes del mundo, podría recomendarse el escrutinio para EC en mujeres con infertilidad, en especial en quienes padecen infertilidad inexplicable.

Seroprevalencia de enfermedad celiaca en pacientes con infertilidad. Un estudio de casos y controles / Celiac disease seroprevalence in patients with infertility. A case-control study

Resumen Antecedentes: Aunque los pacientes con enfermedad celiaca (EC) tienen en su mayoría manifestaciones digestivas, algunos pueden presentarlas de índole extraintestinal (atípicas), como anemia crónica, ataxia y trastornos de la fertilidad. Objetivo: Determinar la prevalencia de anticuerpos relacionados con EC en mujeres mexicanas con trastornos de la fertilidad. Material y métodos: Estudio de casos y controles de mujeres que acudieron a valoración por trastornos de la fertilidad en un centro especializado. Se cuantificó h-tTG IgA, gliadina IgA II y gliadina IgG II; los títulos > 30 UI fueron considerados como positivos. Resultados: Se incluyeron 171 casos y 171 controles; 137 pacientes (80.1 %) tuvieron infertilidad y 34 (19.9 %), esterilidad. Ocho pacientes (4.6 %, IC 95 % = 2.3-8.9) tuvieron al menos un marcador positivo para EC comparadas con una mujer del grupo control (0.5 %, IC 95 % = 0.01-3, p = 0.04, razón de momios = 8.3). Seis de las ocho pacientes presentaron infertilidad inexplicable. Conclusiones: Hasta 4.6 % de las mujeres con infertilidad presentó al menos un marcador positivo para EC. Al igual que en otras partes del mundo, podría recomendarse el escrutinio para EC en mujeres con infertilidad, en especial en quienes padecen infertilidad inexplicable.

Abstract Background: Although most patients with celiac disease (CD) have digestive manifestations, in some of them they may be of extraintestinal (atypical) nature, such as chronic anemia, ataxia, and fertility disorders. Objective: To determine the prevalence of CD-related antibodies in Mexican women with fertility disorders. Material and methods: Case-control study of women who attended evaluation for fertility disorders in a specialized center. h-tTG-IgA, gliadin IgA II and gliadin IgG II were quantified; titers > 30 IU were considered positive. Results: One-hundred and seventy-one cases and 171 controls were included; 137 patients (80.1%) had infertility, and 34 (19.9%), sterility. Eight patients (4.6%, 95% CI = 2.3-8.9) had at least one positive marker for CD in comparison with one woman in the control group (0.5%, 95% CI = 0.01-3, p = 0.04, odds ratio = 8.3). Six of the eight patients had unexplained infertility. Conclusions: Up to 4.6% of women with infertility had at least one positive marker for CD. As in other parts of the world, screening for CD could be recommended in women with infertility, especially in those with unexplained infertility.

Mucosal Vaccination: A Promising Alternative Against Flaviviruses.

The Flaviviridae are a family of positive-sense, single-stranded RNA enveloped viruses, and their members belong to a single genus, Flavivirus. Flaviviruses are found in mosquitoes and ticks; they are etiological agents of: dengue fever, Japanese encephalitis, West Nile virus infection, Zika virus infection, tick-borne encephalitis, and yellow fever, among others. Only a few flavivirus vaccines have been licensed for use in humans: yellow fever, dengue fever, Japanese encephalitis, tick-borne encephalitis, and Kyasanur forest disease. However, improvement is necessary in vaccination strategies and in understanding of the immunological mechanisms involved either in the infection or after vaccination. This is especially important in dengue, due to the immunological complexity of its four serotypes, cross-reactive responses, antibody-dependent enhancement, and immunological interference. In this context, mucosal vaccines represent a promising alternative against flaviviruses. Mucosal vaccination has several advantages, as inducing long-term protective immunity in both mucosal and parenteral tissues. It constitutes a friendly route of antigen administration because it is needle-free and allows for a variety of antigen delivery systems. This has promoted the development of several ways to stimulate immunity through the direct administration of antigens (e.g., inactivated virus, attenuated virus, subunits, and DNA), non-replicating vectors (e.g., nanoparticles, liposomes, bacterial ghosts, and defective-replication viral vectors), and replicating vectors (e.g., Salmonella enterica, Lactococcus lactis, Saccharomyces cerevisiae, and viral vectors). Because of these characteristics, mucosal vaccination has been explored for immunoprophylaxis against pathogens that enter the host through mucosae or parenteral areas. It is suitable against flaviviruses because this type of immunization can stimulate the parenteral responses required after bites from flavivirus-infected insects. This review focuses on the advantages of mucosal vaccine candidates against the most relevant flaviviruses in either humans or animals, providing supporting data on the feasibility of this administration route for future clinical trials.

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). We evaluated the isotype specificity of ZIKV-specific Abs in immune sera and supernatants from stimulated immune PBMC and found that Abs against ZIKV NS1 and virus-like particles were predominantly of the IgG1 isotype. Using a recently developed FluoroSpot assay, we found robust frequencies of NS1-specific Ab-secreting cells in PBMC of individuals who were naturally infected with ZIKV. We developed assays to measure both natural killer cell activation by flow cytometry and target cell lysis of ZIKV NS1-expressing cells using an image cytometry assay in the presence of ZIKV NS1 Abs. Our data indicate efficient opsonization of ZIKV NS1-expressing CEM-NKR cell lines using ZIKV-immune but not ZIKV-naïve sera, a prerequisite of ADCC. Furthermore, sera from immune donors were able to induce both NK cell degranulation and lysis of ZIKV NS1 CEM-NKR cells in vitro. Our data suggest that ADCC is a possible mechanism for ZIKV NS1 Abs to eliminate virally infected target cells.

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. To measure B cell responses, PBMC were stimulated with IL-2 plus R848 and culture supernatants were tested for DENV-binding antibodies by ELISA. To measure T cell responses, PBMC were stimulated in dual-color ELISPOT assays with overlapping peptide pools of structural and non-structural proteins from the four DENV types. B cell responses were low to one or more DENV types prior to symptomatic infection and increased with reactivity to all four types after infection. Subjects who had a subclinical infection or who did not experience a DENV infection during the study period showed strong memory B cell responses to all four DENV types. T cell responses to DENV peptides demonstrated a cytokine hierarchy of IFN-γ > IL-2 > IFN-γ/IL-2. T cell responses were low or absent prior to secondary infections. The trends in T cell responses to DENV peptides over 3 year post-infection were highly variable, but subjects who had experienced a secondary DENV1 infection showed higher cytokine responses compared to subjects who had experienced a secondary DENV2 or subclinical infection. The longitudinal nature of our study demonstrates persistent memory B cell responses over years and a lasting but variable impact of secondary DENV infection on DENV-specific T cell responses.

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

Follicular helper T cells (TFH) 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 TFH (pTFH) are the counterpart of TFH found in the circulation, which resemble TFH in many aspects of their phenotype and function. The CD4+ pTFH 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. This review will discuss recent findings of pTFH in human acute viral diseases with a focus on dengue infection.

Elevated circulating levels of IL-21 and IL-22 define a cytokine signature profile in type 2 autoimmune hepatitis patients.

UNLABELLED:  Background and aims. Autoimmune hepatitis (AIH) is a chronic inflammatory condition of the liver in which the immunological mechanisms involved in tissue destruction and/or repair are still unclear. Different pro-inflammatory cytokines have been shown to play a determinant role in AIH pathogenesis. Here, we aim to compare the circulating levels of pro- and anti-inflammatory cytokines such as IL-6, TNF-?, IL-17A/F, IL-21, IL-22, IL-23, and IL-10 in patients with type 2 AIH compared to patients with type 1 AIH and healthy controls (HC). Fourty-six Mexican patients with AIH were recruited in our study. Patients were classified as type 1 or 2 AIH based on immune serological markers. Fourty-four serum samples from healthy individuals were included as controls. Serum cytokine levels were determined by ELISA technique. RESULTS: Compared to healthy controls, serum levels of IL-17F, IL-21, IL-23, IL-10, IL-6, and TNF-?, but not IL-17A and IL-22, were significantly increased in AIH patients. When patients were grouped by aminotransferase activity, a biomarker of active disease, a positive correlation between serum IL-17F and alanine transaminase (rs: 0.4739; P = 0.0009) and aspartate transaminase (rs: 0.4984; P = 0.0004) levels was found. A cytokine signature profile associated with type 2 AIH was characterized by high serum IL-21 (type 1 AIH: 0.66 pg/mL; type 2 AIH: 331.1 pg/mL; P = 0.0042) and IL-22 (type 1 AIH: 0.1 pg/mL; type 2 AIH: 55.26 pg/mL; P = 0.0028) levels. CONCLUSIONS: We show for the first time, differential regulation of certain pro-inflammatory cytokines associated with disease progression and AIH type in Mexican patients.

Evaluation of the SD BIOLINE Dengue Duo rapid test in the course of acute and convalescent dengue infections in a Mexican endemic region.

In this study, we evaluated the performance of a rapid test, the SD BIOLINE Dengue Duo (SD BDD) kit, with a panel of serum samples from 310 Mexican patients with diagnosis of dengue infection previously confirmed by reference enzyme-linked immunosorbent assay tests. Eighty-seven negative samples from other febrile illnesses were included as controls. The SD BDD showed an overall sensitivity of 90.65% and specificity of 89.66%. No statistically significant differences were found in the sensitivity of the SD BDD kit compared between primary or secondary infections (87.05% versus 93.57%, respectively, P = 0.0761) and dengue fever or dengue hemorrhagic fever cases (90.77% versus 89.74%, respectively, P = 0.7716). However, a higher sensitivity in the acute phase of dengue infection was found compared with the convalescent phase (93.03% versus 81.82%, respectively, P = 0.0089). These results indicate that the SD BDD kit is a useful tool to diagnose dengue infections, both in primary or secondary infections and mainly during the acute phase.