Splenic accumulation of IL-10 mRNA in T cells distinct from CD4+CD25+ (Foxp3) regulatory T cells in human visceral leishmaniasis

Visceral leishmaniasis (VL) is a life-threatening disease characterized by uncontrolled parasitization of the spleen, liver, and bone marrow. Interleukin (IL)-10 has been implicated in the suppression of host immunity in human VL based on the elevated levels of IL-10 observed in plasma and lesional tissue, and its role in preventing clearance of Leishmania donovani in murine models of VL. The aim of this study was to identify the cellular source of IL-10 in human VL and determine if CD4+CD25+ (Foxp3high) regulatory T (T reg) cells are associated with active disease. We analyzed surface marker and gene expression in peripheral blood mononuclear cells and splenic aspirates from Indian VL patients before and 3–4 wk after treatment with Amphotericin B. The results did not point to an important role for natural CD4+CD25+ (Foxp3high) T reg cells in human VL. They did not accumulate in and were not a major source of IL-10 in the spleen, and their removal did not rescue antigen-specific interferon γ responses. In contrast, splenic T cells depleted of CD25+ cells expressed the highest levels of IL-10 mRNA and were the predominant lymphocyte population in the VL spleen. The elevated levels of IL-10 in VL plasma significantly enhanced the growth of L. donovani amastigotes in human macrophages. The data implicate IL-10–producing CD25−Foxp3− T cells in the pathogenesis of human VL

Macrophage migration inhibitory factor (MIF) is essential for Type 2 effector cell immunity to an intestinal helminth parasite

Immunity to intestinal helminths is known to require both innate and adaptive components of the immune system activated alongthe Type 2 IL-4R/STAT6-dependent pathway. We have found that macrophage migration inhibitory factor (MIF) is essential for thedevelopment of effective immunity to the intestinal helminth Heligmosomoides polygyrus, even following vaccination which inducessterile immunity in wild-type mice. A chemical inhibitor of MIF, 4-IPP, was similarly found to compromise anti-parasite immunity.Cellular analyses found that the adaptive arm of the immune response, including IgG1 antibody responses and Th2-derivedcytokines, was intact and that Foxp3+ T regulatory cell responses were unaltered in the absence of MIF. However, MIF was found tobe an essential cytokine for innate cells, with ablated eosinophilia and ILC2 responses, and delayed recruitment and activation ofmacrophages to the M2 phenotype (expressing Arginase 1, Chil3, and RΕLM‐alpha) upon infection of MIF‐deficient mice; amacrophage deficit was also seen in wild-type BALB/c mice exposed to 4-IPP. Gene expression analysis of intestinal and lymph nodetissues from MIF-deficient and -sufficient infected mice indicated significantly reduced levels of Arl2bp, encoding a factor involved innuclear localization of STAT3. We further found that STAT3-deficient macrophages expressed less Arginase-1, and that mice lackingSTAT3 in the myeloid compartment (LysMCrexSTAT3fl/fl) were unable to reject a secondary infection with H. polygyrus. We thusconclude that in the context of a Type 2 infection, MIF plays a critical role in polarizing macrophages into the protectivealternatively-activated phenotype, and that STAT3 signaling may make a previously unrecognized contribution to immunity tohelminths

Effect of Acute Plasmodium falciparum Malaria on Reactivation and Shedding of the Eight Human Herpes Viruses

Human herpes viruses (HHVs) are widely distributed pathogens. In immuno-competent individuals their clinical outcomes are generally benign but in immuno-compromised hosts, primary infection or extensive viral reactivation can lead to critical diseases. Plasmodium falciparum malaria profoundly affects the host immune system. In this retrospective study, we evaluated the direct effect of acute P. falciparum infection on reactivation and shedding of all known human herpes viruses (HSV-1, HSV-2, VZV, EBV, CMV, HHV-6, HHV-7, HHV-8). We monitored their presence by real time PCR in plasma and saliva of Ugandan children with malaria at the day of admission to the hospital (day-0) and 14 days later (after treatment), or in children with mild infections unrelated to malaria. For each child screened in this study, at least one type of HHV was detected in the saliva. HHV-7 and HHV-6 were detected in more than 70% of the samples and CMV in approximately half. HSV-1, HSV-2, VZV and HHV-8 were detected at lower frequency. During salivary shedding the highest mean viral load was observed for HSV-1 followed by EBV, HHV-7, HHV-6, CMV and HHV-8. After anti-malarial treatment the salivary HSV-1 levels were profoundly diminished or totally cleared. Similarly, four children with malaria had high levels of circulating EBV at day-0, levels that were cleared after anti-malarial treatment confirming the association between P. falciparum infection and EBV reactivation. This study shows that acute P. falciparum infection can contribute to EBV reactivation in the blood and HSV-1 reactivation in the oral cavity. Taken together our results call for further studies investigating the potential clinical implications of HHVs reactivation in children suffering from malaria

A role for NK cells in innate immunity against human leishmaniasis

Leishmaniasis is a group name for a spectrum of diseases caused by intracellular protozoa belonging to the family Leishmania. The parasites has been widely used as a tool to study the Th1 / Th2 paradigm of resistance and susceptibility in mice. A role of NK cells in leishmaniasis has been implicated, but not fully explored. In this thesis work we have continued previous studies exploring the cellular, in particular NK cell, responses to Leishmania antigens in blood mononuclear cells from humans with no history of leishmaniasis. It is of importance to study the responses in unexposed donors since they a) represent a potential group to whom a vaccine will be given and b) will give information about the innate responses to Leishmania, which may be of importance in determining disease outcome and/or protection. The last part of this work investigated the contribution of NK cells in the development of human cutaneous leishmaniasis. It has long been known that individuals who have healed from cutaneous leishinaniasis are protected against further disease. Thus, a vaccine against leishmaniasis would appear to be achievable. Vaccine studies performed on humans have shown that live Leishmania vaccine induces solid protection, while heat-killed Leishmania + BCG induce variable protection. We tested if the differences in the efficacy of the two types of vaccines were in part due to differential cellular responses initially induced by live and dead parasites. Results show clear differences in the type of responses evoked by live and dead parasites. Live promastigotes induced IFNgamma secretion in NK cells, while killed promastigotes tended to induce Me cells proliferation. Furthermore, we demonstrate that live promastigotes independent, of other cell subsets and IL-12, could induce NK cells to IFFgamma secretion, Suggesting that NK cells can contribute independently and very early on in the defence against pathogens. A number of vaccine candidates against leishmaniasis, such as Leish-111f, LACK (Leishmania homologue of receptors for activated C kinase) and the amastigote antigens P-2, P-4 and P-8, have demonstrated encouraging results in mice but, are yet to prove themselves in humans. We tested the stimulating capacity of P-2, P-4 and P-8 in healthy donors and found P-2 to have most reactivity. A similar pattern of reactivity, but with enhanced magnitude was observed when cells were stimulated with LACK. Both LACK and P-2 stimulated cells to proliferation and secretion of IFFgamma and IL- 10. Both T cells and NK cells were involved in these responses. Furthermore, we demonstrated that the induction of IFFgamma as well as proliferation to these vaccine candidates were MHC class 11 dependent, whereas IL- 10 secretion tended to be enhanced by blocking MHC class Il. Direct activation of NK cells could not be achieved by LACK or P-2 requiring antigen presenting cells for induction of NK responses. NK cells have been implicated in protection and healing of cutaneous leishmaniasis. To follow up on these data and data from unexposed individuals we have evaluated the contribution of NK cells to IFFgamma response in cells from Iranian patients with active cutaneous leishmaniasis. Initial cross sectional studies indicated that purified NK cells from active cutaneous leishmaniasis patients had reduced ability to secrete IFNgamma compared to cells from healthy controls. Furthermore, in cured patients, Me cells appeared to downregulate the NK cell induced IFNgamma. However, when cytokines (IFNgamma and IL-13) were evaluated in a longitudinal study in individual donors before and after artificial infection we found that NK cells contributed significantly and equally to the cytokine response both before and nine months after infection, when most of the donors showed signs of disease. The choice of study group and infection dose may have contributed to these unexpected results. The cumulative results of the studies continue to suggest a role for NK cells in the control of leishmaniasis

DataSheet_1_T cell kinetics reveal expansion of distinct lung T cell subsets in acute versus in resolved influenza virus infection.docx

Influenza virus infection is restricted to airway-associated tissues and elicits both cellular and humoral responses ultimately resulting in generation of memory cells able to initiate a rapid immune response against re-infections. Resident memory T cells confer protection at the site of infection where lung-resident memory T cells are important for protecting the host against homologous and heterologous influenza virus infections. Mapping kinetics of local and systemic T cell memory formation is needed to better understand the role different T cells have in viral control and protection. After infecting BALB/c mice with influenza virus strain A/Puerto Rico/8/1934 H1N1 the main proportion of activated T cells and B cells expressing the early activation marker CD69 was detected in lungs and lung-draining mediastinal lymph nodes. Increased frequencies of activated cells were also observed in the peripheral lymphoid organs spleen, inguinal lymph nodes and mesenteric lymph nodes. Likewise, antigen-specific T cells were most abundant in lungs and mediastinal lymph nodes but present in all organs studied. CD8+CD103-CD49a+ lung-resident T cells expanded simultaneously with timing of viral clearance whereas CD8+CD103+CD49a+ lung-resident T cells was the most abundant subset after resolution of infection and antigen-specific, lung-resident T cells were detected up to seven months after infection. In conclusion, the results in this detailed kinetic study demonstrate that influenza virus infection elicits adaptive immune responses mainly in respiratory tract-associated tissues and that distinct subsets of lung-resident T cells expand at different time points during infection. These findings contribute to the understanding of the adaptive immune response locally and systemically following influenza virus infection and call for further studies on the roles of the lung-resident T cell subsets.</p

Risks in the visual environment such as glare, illuminance, and luminance ratio - risk assessments made with visual ergonomics risk assessment method - VERAM - a descriptive paper

The visual environment has an impact on subjective strain and headaches. A visual ergonomics risk assessment method, VERAM, was used on 217 workplaces, and consists of both of a subjective questionnaire and an objective risk assessment, the objective risks are presented in this paper. The risk for daylight was assessed to be yellow (risk) or red (high risk) at 53% of the workplaces and the risk for glare was yellow or red at 66%. The assessment of the lighting design showed a yellow or red risk at 44% of the workplaces and the illuminance was assessed to be insufficient at 49% of the workplaces. Flicker or TLM (temporal light modulation) was assessed to be a problem among 33%. These results show that the design of the visual environment is in most cases not performed in a satisfying way. To increase wellbeing, health and performance a good visual environment is essential

Evaluation of Blood Agar Microtiter Plates for Culturing Leishmania Parasites To Titrate Parasite Burden in Spleen and Peripheral Blood of Patients with Visceral Leishmaniasis▿

Serial dilution of blood and spleen biopsy specimens, plated on Novy-MacNeal-Nicolle (NNN) blood agar using microtiter culture plates, is a sensitive and reproducible method for detection and growth of Leishmania parasites. Plates could be easily monitored, and growth could be rapidly detected. Moreover, parasite number may be estimated using this technique

Differences in Nutritional and Health Status in School Children from the Highlands and Lowlands of Bolivia.

Children in the Bolivian Andes are exposed to endemic infections and meager nourishment, and live under poor hygienic conditions. The prevention of children malnutrition is a priority in many countries including Bolivia. In this study, the health status of schoolchildren in Taraco, a Puna district, at 4,000 meters above sea level (masl) and in Caranavi, at 650 masl in the wealthier subtropical valleys, was compared. The weight, height, and hematological and biochemical parameters in blood, parasites in stool, and clinical information in 120 children from rural Taraco and in 96 from semi-urban Caranavi, both predominantly of Aymara ethnicity, were registered. Eleven percent of Taraco children were undernourished compared with 3% in Caranavi. Instead, 41% of the children in Caranavi were obese or overweight, compared with 8% in Taraco. Anemia was found in 74% of the children in Taraco compared with 7% in Caranavi. Albumin levels were normal in all samples, albeit lower in Taraco. Similar and normal serum zinc levels were measured in both groups. Approximately 60% of the children in both locations showed insufficient vitamin D levels, with lower levels in Taraco children. Hymenolepis nana and Entamoeba coli, parasites determinant of poor hygienic conditions, were respectively detected in 78% and 21% of fecal samples from Taraco, and in 29% and 8% of samples from Caranavi. We show increased anemia, nutritional deficiencies, and indications of poor hygienic conditions in highlands compared with lowlands. The prevalence of obesity in the lowlands demands addressing diverse nutritional deficiencies in the regions of Bolivia