Long-term impact of congenital toxoplasmosis on phenotypic and functional features of circulating leukocytes from infants one year after treatment onset.

Changes in immune response of children with congenital toxoplasmosis (CT) regarding infection evolution and therapeutic intervention was addressed. Infants with CT presented increased counts of monocytes, CD3-CD16-CD56High, CD3+CD56+ and CD4+ T-cells 1-year after treatment onset (TOXO1-yearAT). Smaller numbers of CD3-CD16-CD56+ and TCRγδ+ T-cells were specifically observed in infants with retinochoroidal lesions (L(+)). When infants were classified based on the baseline status, expansion of CD3-CD16-CD56High and CD4+ T-cells were observed in L(+) who had active, active/cicatricial or cicatricial lesions. Infants who had active or active/cicatricial lesions display augmented numbers of monocytes, CD3-CD16+CD56+, CD3+CD56+, CD8+DR+ and TCRγδ+ T-cells and those with active/cicatricial or cicatricial at baseline displayed increase in CD14+CD64+ monocytes. Moreover, all L(+) had increased IFN-γ+ and IL-10+ CD4+ T-cells, while L(-) had increased ratios of TNF+, IFN-γ+ and IL-4+ NK-cells upon antigen-specific stimulation. Persistent alterations in leukocytes in TOXO1-yearAT suggest long-term sequels in the immune system of infants with CT.

T-cells producing multiple combinations of IFNγ, TNF and IL10 are associated with mild forms of dengue infection.

Multifunctional interleukin 10 (IL10)+ Th1 cells have been implicated in favorable evolution of many infectious diseases, promoting an efficacious immune response while limiting immunopathology. Here, we investigated the presence of multifunctional CD4+ and CD8+ T-cells that expressed interferon gamma (IFNγ), IL10 and tumor necrosis factor (TNF), or its combinations during dengue infection. Peripheral blood mononuclear cells (PBMCs) from outpatients with dengue (mild dengue forms) and hospitalized patients (or patients with dengue with warning signs and severe dengue) were cultured in the presence of envelope (ENV) or NS3 peptide libraries of DENV during critical (hospitalization period) and convalescence phases. The production of IFNγ, IL10 and TNF by CD4+ and CD8+ T-cells was assessed by flow cytometry. Our data show that patients with mild dengue, when compared with patients with dengue with warning signs and severe dengue, presented higher frequencies of multifunctional T-cells like NS3-specific IFNγ/IL10-producing CD4+ T-cells in critical phase and NS3- and ENV-specific CD8+ T-cells producing IFNγ/IL10. In addition, NS3-specific CD8+ T-cells producing high levels of IFNγ/TNF and IFNγ/TNF/IL10 were also observed in the mild dengue group. We observed that multifunctional T-cells produced higher levels of cytokines as measured by intracellular content when compared with single producer T-cells. Importantly, multifunctional CD4+ and CD8+ T-cells producing IFNγ, TNF and IL10 simultaneously displayed positive correlation with platelet levels, suggesting a protective role of this population. The presence of IL10+ Th1 and IL10+ Tc1 multifunctional cells was associated with mild dengue presentation, suggesting that these cells play a role in clinical evolution of dengue infection.

T follicular helper cells regulate the activation of B lymphocytes and antibody production during Plasmodium vivax infection.

Although the importance of humoral immunity to malaria has been established, factors that control antibody production are poorly understood. Follicular helper T cells (Tfh cells) are pivotal for generating high-affinity, long-lived antibody responses. While it has been proposed that expansion of antigen-specific Tfh cells, interleukin (IL) 21 production and robust germinal center formation are associated with protection against malaria in mice, whether Tfh cells are found during Plasmodium vivax (P. vivax) infection and if they play a role during disease remains unknown. Our goal was to define the role of Tfh cells during P. vivax malaria. We demonstrate that P. vivax infection triggers IL-21 production and an increase in Tfh cells (PD-1+ICOS+CXCR5+CD45RO+CD4+CD3+). As expected, FACS-sorted Tfh cells, the primary source of IL-21, induced immunoglobulin production by purified naïve B cells. Furthermore, we found that P. vivax infection alters the B cell compartment and these alterations were dependent on the number of previous infections. First exposure leads to increased proportions of activated and atypical memory B cells and decreased frequencies of classical memory B cells, whereas patients that experienced multiple episodes displayed lower proportions of atypical B cells and higher frequencies of classical memory B cells. Despite the limited sample size, but consistent with the latter finding, the data suggest that patients who had more than five infections harbored more Tfh cells and produce more specific antibodies. P. vivax infection triggers IL-21 production by Tfh that impact B cell responses in humans.

Dendritic cells, macrophages, NK and CD8+ T lymphocytes play pivotal roles in controlling HSV-1 in the trigeminal ganglia by producing IL1-beta, iNOS and granzyme B.

BACKGROUND: Herpes simplex virus type 1 (HSV-1) cause not only mild symptoms but also blindness and encephalitis. It was previously shown that the immune response against HSV-1 occurs mainly in the trigeminal ganglia (TG) and that Toll-like receptors 2 and 9 (TLR2/9) are important in mediating this response. It was also demonstrated that iNOS (nitric oxide synthase) and interleukin 1 beta (IL-1ß) play an essential role in the defense against HSV-1 infection. Importantly, the present work aimed to identify the primary cells responsible for iNOS and IL-1ß production and search for other important molecules and cells that might or might not depend on TLR2/9 receptors to mediate the immune response against HSV-1. METHODS: C57BL/6 (wild type, WT) and TLR2/9-/- mice were infected by the intranasal route with HSV-1 (1 × 106 p.f.u.). Cells were obtained from the TG and spleen tissues and the profile of immune cells was determined by flow cytometry in infected and mock infected WT and knockout mice. The percentage of cells producing iNOS, IL-1ß, granzyme B and perforin was also determined by flow cytometry. Chemokine monocyte chemoattractant protein-1 (MCP1) was measured by Cytometric Bead Array (CBA) in the TG, spleen and lung. Expression of type I interferons (IFNs), interleukins (IL) 5 and 10, IL-1ß and granzyme B were quantified by real time PCR. RESULTS: The results indicate that dendritic cells (DCs) and monocytes/macrophages (Mo/Mϕ) were the main sources of IL-1ß and iNOS, respectively, which, together with type I IFNs, were essential for the immune response against HSV-1. Additionally, we showed that granzyme B produced by CD8+ T and NK lymphocytes and MCP-1 were also important for this immune response. Moreover, our data indicate that the robust production of MCP-1 and granzyme B is either TLR-independent or down regulated by TLRs and occurs in the TG of TLR2/9-/- infected mice. CONCLUSION: Taken together, our data provide strong evidence that the responses mediated by DCs, Mo/Mϕ, NK and CD8+ T lymphocytes through IL-1ß, iNOS and granzyme B production, respectively, together with the production of type I IFN early in the infection, are crucial to host defense against HSV-1.

Signatures of CD4+ T and B cells are associated with distinct stages of chronic chagasic cardiomyopathy.

Introduction: Chagas disease is a neglected parasitic disease caused by Trypanosoma cruzi. While most patients are asymptomatic, around 30% develop Chronic Chagasic Cardiomyopathy (CCC). Methods: Here, we employed high-dimensional flow cytometry to analyze CD4+ T and B cell compartments in patients during the chronic phase of Chagas disease, presenting the asymptomatic and mild or moderate/severe cardiac clinical forms. Results: Effector CD27-CD4+ T cells were expanded in both CCC groups, and only mild CCC patients showed higher frequencies of effector memory and T follicular helper (Tfh) cells than healthy donors (CTL) and asymptomatic patients. Unsupervised analysis confirmed these findings and further revealed the expansion of a specific subpopulation composed of Tfh, transitional, and central memory CD4+ T cells bearing a phenotype associated with strong activation, differentiation, and exhaustion in patients with mild but not moderate/severe CCC. In contrast, patients with mild and moderate/severe CCC had lower frequencies of CD4+ T cells expressing lower levels of activation markers, suggesting resting status, than CTL. Regarding the B cell compartment, no alterations were found in naïve CD21-, memory cells expressing IgM or IgD, marginal zone, and plasma cells in patients with Chagas disease. However, expansion of class-switched activated and atypical memory B cells was observed in all clinical forms, and more substantially in mild CCC patients. Discussion: Taken together, our results showed that T. cruzi infection triggers changes in CD4+ T and B cell compartments that are more pronounced in the mild CCC clinical form, suggesting an orchestrated cellular communication during Chagas disease. Conclusion: Overall, these findings reinforce the heterogeneity and complexity of the immune response in patients with chronic Chagas disease and may provide new insights into disease pathology and potential markers to guide clinical decisions.

Immune response induced by standard and fractional doses of 17DD yellow fever vaccine.

The re-emergence of yellow fever (YF) urged new mass vaccination campaigns and, in 2017, the World Health Organization approved the use of the fractional dose (FD) of the YF vaccine due to stock shortage. In an observational cross-sectional investigation, we have assessed viremia, antibodies, soluble mediators and effector and memory T and B-cells induced by primary vaccination of volunteers with FD and standard dose (SD). Similar viremia and levels of antibodies and soluble markers were induced early after immunization. However, a faster decrease in the latter was observed after SD. The FD led to a sustained expansion of helper T-cells and an increased expression of activation markers on T-cells early after vaccination. Although with different kinetics, expansion of plasma cells was induced upon SD and FD immunization. Integrative analysis reveals that FD induces a more complex network involving follicular helper T cells and B-cells than SD. Our findings substantiate that FD can replace SD inducing robust correlates of protective immune response against YF.

Serum soluble mediator waves and networks along healthy ageing.

The ageing process is a complex phenomenon that impacts the immune system, leading to changes in the pattern of serum soluble mediators. In the present study, the serum levels of several chemokines, pro-inflammatory/regulatory cytokines and growth factors were quantified by high-throughput microbeads array in serum samples from 541 healthy subjects at distinct age ranges (3Yrs to >70Yrs). A broad increase in serum soluble mediators was observed at 6-10Yrs with subsequent decline at 11-20Yrs and 21-30Yrs followed by a second round of upregulation starting at 31-40Yrs, with a large increase at 51-60Yrs and a marked decline at age >70Yrs. Heatmap and signatures of serum soluble mediators demonstrated a bimodal profile with one peak at 6-10Yrs and a second wave around 61-70Yrs. A universal decline was observed later at age >70Yrs. In males, the second wave started earlier at 31-40Yrs with a peak at 51-60Yrs and a further smooth decline towards >70Yrs. Conversely, in females, the first peak extended from 3-5Yrs to 6-10Yrs and the second wave starting around 41-50Yrs with a peak at 61-70Yrs followed by a sharp decline at >70Yrs. Overall, CCL11, CXCL8, IL-1ß, IL-6 were underscored as universal age-related biomarkers with higher levels observed at later age ranges (after 31-40Yrs) and TNF with increased levels starting at early age ranges. Data analysis demonstrated that the highest neighborhood connectivity amongst soluble mediators occurred at 3-5Yrs, with distinct declining and strengthening rhythm in males and females. Notably, rebuilding re-arrangements were usually earlier and more frequent in females (at 11-20Yrs, 51-60Yrs and >70Yrs) than in males (at 21-30Yrs, 61-70Yrs). Overall, this study provided a comprehensive landscape of evidence portrayed by distinct waves, rhythms and dynamic network connectivity along healthy ageing with differences in magnitude and timing reported for sexes.

Serum Soluble Mediator Profiles and Networks During Acute Infection With Distinct DENV Serotypes.

A panoramic analysis of chemokines, pro-inflammatory/regulatory cytokines, and growth factors was performed in serum samples from patients with acute DENV infection (n=317) by a high-throughput microbeads array. Most soluble mediators analyzed were increased in DENV patients regardless of the DENV serotype. The substantial increase (≥10-fold) of CXCL10, IL-6, and IFN-γ, and decreased levels of PDGF (<0.4-fold) was universally identified in all DENV serotypes. Of note, increased levels of CXCL8, CCL4, and IL-12 (≥3-9-fold) were selectively observed in DENV2 as compared to DENV1 and DENV4. Heatmap and biomarker signatures further illustrated the massive release of soluble mediators observed in DENV patients, confirming the marked increase of several soluble mediators in DENV2. Integrative correlation matrices and networks showed that DENV infection exhibited higher connectivity among soluble mediators. Of note, DENV2 displayed a more complex network, with higher connectivity involving a higher number of soluble mediators. The timeline kinetics (Day 0-1, D2, D3, D4-6) analysis additionally demonstrated differences among DENV serotypes. While DENV1 triggers a progressive increase of soluble mediators towards D3 and with a decline at D4-6, DENV2 and DENV4 develop with a progressive increase towards D4-6 with an early plateau observed in DENV4. Overall, our results provided a comprehensive overview of the immune response elicited by DENV infection, revealing that infection with distinct DENV serotypes causes distinct profiles, rhythms, and dynamic network connectivity of soluble mediators. Altogether, these findings may provide novel insights to understand the pathogenesis of acute infection with distinct DENV serotypes.

Schistosoma mansoni Infection Is Impacted by Malnutrition.

Schistosomiasis remains one of the most important neglected tropical diseases in the world. It mainly affects developing countries, where it often coexists with malnutrition. Despite this, few studies have investigated the relationship between schistosomiasis and malnutrition. Herein, we evaluate the impact of malnutrition on experimental S. mansoni infection. Mice were divided into 5 groups: Control (Ctrl) diet (14% protein and 10% lipids), low-protein 3% (LP 3%), low-protein 8% (LP 8%), low-fat 2.5% (LF 2.5%), and low-fat 5% (LF 5%). Mice were fed with their respective diets and were infected when a difference of approximately 20% in the body weight between mice from any experimental group and mice from the control group was achieved. Nutritional, parasitological, and immunological parameters were assessed either just before infection and/or approximately 50 days later before mice were perfused. Our results showed that the 3% low-protein diet was the only one capable of establishing malnutrition in mice. Mice fed with this diet showed: (i) significant reduction in body weight and serum albumin levels before infection, (ii) decreased levels of all biochemical parameters evaluated before perfusion, (iii) decreased numbers of schistosome eggs trapped in intestines and impaired parasite fecundity, (iv) a delay in the granuloma development with a smaller granuloma area, and (v) reduced levels of IL-4 and IFN-γ in the liver. Our findings demonstrate that low protein supply leads to malnutrition in mice and impacts the cytokine milieu in the liver and granuloma formation. Additionally, the establishment of our murine malnutrition model will enable future studies aiming to better understand the complex relationships between nutrition, immune responses, and infection outcome.

Plasmodium vivax Infection Alters Mitochondrial Metabolism in Human Monocytes.

Monocytes play an important role in the host defense against Plasmodium vivax as the main source of inflammatory cytokines and mitochondrial reactive oxygen species (mROS). Here, we show that monocyte metabolism is altered during human P. vivax malaria, with mitochondria playing a major function in this switch. The process involves a reprograming in which the cells increase glucose uptake and produce ATP via glycolysis instead of oxidative phosphorylation. P. vivax infection results in dysregulated mitochondrial gene expression and in altered membrane potential leading to mROS increase rather than ATP production. When monocytes were incubated with P. vivax-infected reticulocytes, mitochondria colocalized with phagolysosomes containing parasites representing an important source mROS. Importantly, the mitochondrial enzyme superoxide dismutase 2 (SOD2) is simultaneously induced in monocytes from malaria patients. Taken together, the monocyte metabolic reprograming with an increased mROS production may contribute to protective responses against P. vivax while triggering immunomodulatory mechanisms to circumvent tissue damage. IMPORTANCE Plasmodium vivax is the most widely distributed causative agent of human malaria. To achieve parasite control, the human immune system develops a substantial inflammatory response that is also responsible for the symptoms of the disease. Among the cells involved in this response, monocytes play an important role. Here, we show that monocyte metabolism is altered during malaria, with its mitochondria playing a major function in this switch. This change involves a reprograming process in which the cells increase glucose uptake and produce ATP via glycolysis instead of oxidative phosphorylation. The resulting altered mitochondrial membrane potential leads to an increase in mitochondrial reactive oxygen species rather than ATP. These data suggest that agents that change metabolism should be investigated and used with caution during malaria.

Asymptomatic Plasmodium vivax malaria in the Brazilian Amazon: Submicroscopic parasitemic blood infects Nyssorhynchus darlingi.

Individuals with asymptomatic infection due to Plasmodium vivax are posited to be important reservoirs of malaria transmission in endemic regions. Here we studied a cohort of P. vivax malaria patients in a suburban area in the Brazilian Amazon. Overall 1,120 individuals were screened for P. vivax infection and 108 (9.6%) had parasitemia detected by qPCR but not by microscopy. Asymptomatic individuals had higher levels of antibodies against P. vivax and similar hematological and biochemical parameters compared to uninfected controls. Blood from asymptomatic individuals with very low parasitemia transmitted P. vivax to the main local vector, Nyssorhynchus darlingi. Lower mosquito infectivity rates were observed when blood from asymptomatic individuals was used in the membrane feeding assay. While blood from symptomatic patients infected 43.4% (199/458) of the mosquitoes, blood from asymptomatic infected 2.5% (43/1,719). However, several asymptomatic individuals maintained parasitemia for several weeks indicating their potential role as an infectious reservoir. These results suggest that asymptomatic individuals are an important source of malaria parasites and Science and Technology for Vaccines granted by Conselho Nacional de may contribute to the transmission of P. vivax in low-endemicity areas of malaria.

Trypanosoma cruzi-induced activation of functionally distinct αß and γδ CD4- CD8- T cells in individuals with polar forms of Chagas' disease.

CD4(-) CD8(-) (double-negative [DN]) T cells have recently been shown to display important immunological functions in human diseases. They express γδ or αß T-cell receptors that recognize lipid/glycolipid antigens presented via the nonclassical major histocompatibility complex molecules of the CD1 family. We recently demonstrated that while αß DN T cells serve primarily to express inflammatory cytokines, γδ DN T cells express mainly interleukin-10 (IL-10) in patients with cutaneous leishmaniasis. We also demonstrated a correlation between DN T cells and the expression of gamma interferon in the acute phase of Trypanosoma cruzi experimental infection. In this work, we sought to investigate whether αß or γδ DN T cells display distinct immunoregulatory potentials in patients with polar forms of human Chagas' disease. Our data showed that in vitro infection with T. cruzi leads to expansion of DN T cells in patients with the indeterminate and severe cardiac clinical forms of the disease. However, while αß DN T cells primarily produce inflammatory cytokines in both forms of the disease, γδ DN T cells display a marked, significant increase in antigen-specific IL-10 expression in indeterminate patients relative to cardiac patients. Finally, higher frequencies of the IL-10-producing γδ DN T cells were correlated with improved clinical measures of cardiac function in the patients, suggesting a protective role for these cells in Chagas' disease. Taken together, these data show distinct functional characteristics for αß and γδ DN T cells associated with distinct morbidity rates and clinical forms in human Chagas' disease.

The emergence of pathogenic TNF/iNOS producing dendritic cells (Tip-DCs) in a malaria model of acute respiratory distress syndrome (ARDS) is dependent on CCR4.

Malaria-associated acute respiratory distress syndrome (MA-ARDS) and acute lung injury (ALI) are complications that cause lung damage and often leads to death. The MA-ARDS/ALI is associated with a Type 1 inflammatory response mediated by T lymphocytes and IFN-γ. Here, we used the Plasmodium berghei NK65 (PbN)-induced MA-ALI/ARDS model that resembles human disease and confirmed that lung CD4+ and CD8+ T cells predominantly expressed Tbet and IFN-γ. Surprisingly, we found that development of MA-ALI/ARDS was dependent on functional CCR4, known to mediate the recruitment of Th2 lymphocytes and regulatory T cells. However, in this Type 1 inflammation-ARDS model, CCR4 was not involved in the recruitment of T lymphocytes, but was required for the emergence of TNF-α/iNOS producing dendritic cells (Tip-DCs) in the lungs. In contrast, recruitment of Tip-DCs and development of MA-ALI/ARDS were not altered in CCR2-/- mice. Importantly, we showed that NOS2-/- mice are resistant to PbN-induced lung damage, indicating that reactive nitrogen species produced by Tip-DCs play an essential role in inducing MA-ARDS/ALI. Lastly, our experiments suggest that production of IFN-γ primarily by CD8+ T cells is required for inducing Tip-DCs differentiation in the lungs and the development of MA-ALI/ARDS model.

IFN-α as a time-sensitive biomarker during Oropouche virus infection in early and late seroconverters.

In the present study, patients with acute OROV fever were classified as early seroconverters (IgM/IgG positive at baseline) or late seroconverters (IgM/IgG negative at baseline) and the timeline kinetics of the production of chemokines and cytokines were assessed at 1-3, 4-7, 8-10 and ≥11 days after patients have reported the first symptoms. Regardless immunoglobulin profile, all OROV fever patients presented higher levels of CXCL8, and IFN-α and lower levels of TNF and IL-10 at baseline as compared to healthy donors (HD). Lower levels of CCL2, CXCL10, and IFN-γ and higher levels of CCL2, CXCL10, IL-6, and IL-17A were detected in early and late seroconverters, respectively, as compared to HD. While early seroconverters presented the increasing levels of CCL2 along the timeline, late seroconverters displayed decreasing levels of CCL2, CXCL10, and IL-6 following days of disease onset. Noteworthy was that IFN-α was revealed as universal biomarker of human OROV fever, while CXCL8 & IL-5 and CXCL10 & IL-17 were consistently observed in early and late seroconverters, respectively. Thus, our results suggest that the production of IFN-α, CXCL10, and IL-17 precede the seroconversion bringing novel insights on the immunological events triggered by the OROV disease.

Impact of synthetic and biological immunomodulatory therapy on the duration of 17DD yellow fever vaccine-induced immunity in rheumatoid arthritis.

BACKGROUND: The 17DD-yellow fever (YF) vaccine induces a long-lasting protective immunity, resulting from humoral and cellular immunological memory. The treatment of rheumatoid arthritis (RA) patients with disease-modifying anti-rheumatic drugs (DMARD) may affect pre-existing 17DD-vaccine protective immunity and increase the risk of acquiring YF infection. Our goal was to determine whether DMARD would affect the duration of YF-specific protective immunity in RA patients. METHODS: A total of 122 RA patients, previously immunized with the 17DD-YF vaccine (1-5, 5-9, and ≥ 10 years) and currently under DMARD therapy, were enrolled in the present investigation. Immunomodulatory therapy encompasses the use of conventional synthetic DMARD alone (csDMARD) or combines with biological DMARD (cs+bDMARD). A total of 226 healthy subjects were recruited as a control group (CONT). Neutralizing antibody responses were measured by a plaque-reduction neutralization test (PRNT), and cellular immunity was evaluated by an in vitro 17DD-YF-specific peripheral blood lymphoproliferative assay. RESULTS: The data demonstrated that csDMARD therapy did not affect the duration of protective immunity induced by the 17DD-YF vaccine compared to that of CONT, as both presented a significant time-dependent decline at 10 years after vaccination. Conversely, cs+bDMARD therapy induced a premature depletion in the main determinants of the vaccine protective response, with diminished PRNT seropositivity levels between 5 and 9 years and impaired effector memory in CD8+ T cells as early as 1-5 years after 17DD-YF vaccination. CONCLUSIONS: These findings could support changing the vaccination schedule of this population, with the possibility of a planned booster dose upon the suspension of bDMARD in cases where this is allowed, even before 10 years following 17DD-YF vaccination. The benefit of a planned booster dose should be evaluated in further studies. TRIAL REGISTRATION: RBR-946bv5 . Date of registration: March 05, 2018. Retrospectively registered.

Monocyte subpopulations as important biomarkers of resistence and susceptibility during experimental infection with Leishmania (Leishmania) major.

Visceral Leishmaniasis is a chronic and lethal, parasitic disease. In the later infection stages, it is known that expressive hematological disorders can be observed, including changes in the frequency and phenotype of certain leukocytes. There is a lack of good prognostic indicators to characterize the on-goin clinical status of the patient. In this study, we have analyzed the frequency of monocyte subpopulations in mice infected with Leishmania major (L. major). Our results show a significant correlation between increased blood monocyte frequency and lesion development in both BALB/c and in the C57BL/6 mice infected with L. major. In BALB/c mice we observed a significant correlation between the frequency of GR1+ monocytes and lesion size. Furthermore, treatment of infected BALB/c mice with Anfotericin B, to resolve lesions, resulted in a lower frequency of GR1+ monocytes compared to untreated infected BALB/c mice. C57BL/6 infected mice, which normally resolve infections, show decreased numbers of monocytes during the healing phase of infection. The results indicate that disease severity can be predicted by analyzing monocyte frequency. Thus, we propose that the frequency of monocytes, can be used to define the severity of the disease as well as the success of the treatment in experimental leishmaniasis.

Distinct patterns of cellular immune response elicited by influenza non-adjuvanted and AS03-adjuvanted monovalent H1N1(pdm09) vaccine.

The study aimed at identifying biomarkers of immune response elicited by non-adjuvanted-(NAV) and adjuvanted-(AV) H1N1(pdm09) vaccines. The results showed that despite both vaccines elicited similar levels of anti-H1N1 antibodies at day30 after vaccination, higher reactivity was observed in AV at day180. While AV induced early changes in cell-surface molecules on monocytes, CD4+, CD8+ T-cells and B-cells, NAV triggered minor changes, starting later on at day3. Furthermore, AV induced a late and persistent increase in TLR gene expression after day3, except for tlr4, while NAV displayed earlier but transient tlr3/4/7/9 up-regulation. Contrasting with NAV, prominent chemokine gene expression (cxcl8,cxcl9,ccl5) and a broad spectrum up-regulation of plasmatic biomarkers (CXCL8,IL-6,IL-1ß,IL-12,IL-10) was evident in AV, which showed a major involvement of TNF and IL-10. Similarly, AV induced a robust IL-10-modulated proinflammatory storm, with early and persistent involvement of TNF-α/IL-12/IFN-γ axis derived from NK-cells, CD4+ and CD8+ T-cells along with promiscuous production of IL-4/IL-5/IL-13. Conversely, NAV promotes a concise and restricted intracytoplasmic chemokine/cytokine response, essentially mediated by TNF-α and IL-4, with late IL-10 production by CD8+ T-cells. Systems biology approach underscored that AV guided the formation of an imbricate network characterized by a progressive increase in the number of neighborhood connections amongst innate and adaptive immunity. In AV, the early cross-talk between innate and adaptive immunity, followed by the triad NK/CD4+/CD8+ T-cells at day3, sponsored a later/robust biomarker network. These findings indicate the relevance of adjuvanted vaccination to orchestrate broad, balanced and multifactorial cellular immune events that lead ultimately to a stronger H1N1 humoral immunity.

IgA and IgG1 reactivities assessed by flow cytometry mirror clinical aspects of infants with ocular congenital toxoplasmosis.

This study intended to apply the flow cytometric analysis of IgA and IgG reactivity and intracytoplasmic cytokine analysis to understand and decode the clinical aspects of infants with ocular congenital toxoplasmosis. The Toxoplasma gondii-infected infants (TOXO) were subdivided according to their clinical aspects based on the absence (NRL), presence of active (ARL), active/cicatricial (ACRL) or cicatricial retinochoroidal lesions (CRL) and compared to non-infected controls (NI). The reactivity of anti-T. gondii IgG subclasses resembles the clinical aspects of ocular lesions. IgG and IgG1 discriminate infants with cicatricial lesions (ACRL and CRL) from both ARL and NLR. IgG2 and IgG3 are particularly higher in ACRL and CRL as compared to NLR. No differences were observed when IgG4 reactivity was evaluated. Thus, the results indicated that the reactivity patterns of IgA, IgG and IgG subclasses are able to discriminate ARL, ACRL and CRL from NLR or NI. IgA and IgG subclasses are relevant serological biomarkers with diagnostic and prognostic applicability, respectively. Moreover, IgA and IgG1 were closely related to cytokine production by innate/adaptive immunity cells. IgA reactivity was directly associated to TNF-α-derived from neutrophils, monocytes and CD8(+) T-cells, while IgG1 was inversely correlated with IFN-γ-producing CD4(+) and CD8(+) T-cells but positively correlated with IL-10(+) B-cells. These findings provide insights on the relationship between the cytokine production by innate/adaptive immunity and the antibody pattern of infants with ocular congenital toxoplasmosis. In addition, the present study supports the use of flow cytometric serology as a potential tool for the diagnosis and monitoring of ocular lesions in T. gondii-infected infants in the clinical setting.

IFNs Reset the Differential Capacity of Human Monocyte Subsets to Produce IL-12 in Response to Microbial Stimulation

Human primary monocytes are composed of a minor, more mature CD16+(CD14low/neg) population and a major CD16neg(CD14+) subset. The specific functions of CD16+ versus CD16neg monocytes in steady state or inflammation remain poorly understood. In previous work, we found that IL-12 is selectively produced by the CD16+ subset in response to the protozoan pathogen, Toxoplasma gondii In this study, we demonstrated that this differential responsiveness correlates with the presence of an IFN-induced transcriptional signature in CD16+ monocytes already at baseline. Consistent with this observation, we found that in vitro IFN-γ priming overcomes the defect in the IL-12 response of the CD16neg subset. In contrast, pretreatment with IFN-γ had only a minor effect on IL-12p40 secretion by the CD16+ population. Moreover, inhibition of the mTOR pathway also selectively increased the IL-12 response in CD16neg but not in CD16+ monocytes. We further demonstrate that in contrast to IFN-γ, IFN-α fails to promote IL-12 production by the CD16neg subset and blocks the effect of IFN-γ priming. Based on these observations, we propose that the acquisition of IL-12 responsiveness by peripheral blood monocyte subsets depends on extrinsic signals experienced during their developmental progression in vivo. This process can be overridden during inflammation by the opposing regulatory effects of type I and II IFN as well as the mTOR inhibition.

Type I Interferon Transcriptional Signature in Neutrophils and Low-Density Granulocytes Are Associated with Tissue Damage in Malaria.

Neutrophils are the most abundant leukocyte population in the bloodstream, the primary compartment of Plasmodium sp. infection. However, the role of these polymorphonuclear cells in mediating either the resistance or the pathogenesis of malaria is poorly understood. We report that circulating neutrophils from malaria patients are highly activated, as indicated by a strong type I interferon transcriptional signature, increased expression of surface activation markers, enhanced release of reactive oxygen species and myeloperoxidase, and a high frequency of low-density granulocytes. The activation of neutrophils was associated with increased levels of serum alanine and aspartate aminotransferases, indicating liver damage. In a rodent malaria model, we observed intense recruitment of neutrophils to liver sinusoids. Neutrophil migration and IL-1ß and chemokine expression as well as liver damage were all dependent on type I interferon signaling. The data suggest that type I interferon signaling has a central role in neutrophil activation and malaria pathogenesis.