Identification of a mutated receptor-like protein tyrosine phosphatase kappa as a novel,class II HLA-restricted melanoma antigen

Recent studies increasingly point to a pivotal role of CD4(+) T cells in human anti-tumor immune response. Here we show that lymphocytes purified from a tumor-infiltrated lymph node of a melanoma patient that had remained disease free for 10 years after surgical resection of a lymph node metastasis comprised oligoclonal class II HLA-restricted CD4(+) T cells recognizing the autologous tumor cells in vitro. In fact, the CD4(+) T cell clones isolated from these lymphocytes displayed a tumor-specific, cytotoxic activity in addition to a Th1-like cytokine profile. By a genetic approach, a peptide derived from a mutated receptor-like protein tyrosine phosphatase kappa was identified as a novel HLA-DR10-restricted epitope for all the melanoma-specific CD4(+) T cell clones. The immunogenic peptide was shown to contain the mutated residue that was crucial for T cell recognition and activation. Moreover, a systemic immunity against the mutated peptide was detectable in the patient's peripheral blood T lymphocytes obtained during the disease-free period of follow-up. These findings further support the relevance of CD4(+) T cells directed against mutated epitopes in tumor immunity and provide the rationale for a possible usage of mutated, tumor-specific Ags for immunotherapy of human cancer.     

Reduction of blood pressure,plasma cholesterol,and atherosclerosis by elevated endothelial nitric oxide

In the vascular system, nitric oxide is generated by endothelial NO synthase (eNOS). NO has pleiotropic effects, most of which are believed to be atheroprotective. Therefore, it has been argued that patients suffering from cardiovascular disease could benefit from an increase in eNOS activity. However, increased NO production can cause oxidative damage, cell toxicity, and apoptosis and hence could be atherogenic rather than beneficial. To study the in vivo effects of increased eNOS activity, we created transgenic mice overexpressing human eNOS. Aortic blood pressure was approximately 20 mm Hg lower in the transgenic mice compared with control mice because of lower systemic vascular resistance. The effects of eNOS overexpression on diet-induced atherosclerosis were studied in apolipoprotein E-deficient mice. Elevation of eNOS activity decreased blood pressure ( approximately 20 mm Hg) and plasma levels of cholesterol ( approximately 17%), resulting in a reduction in atherosclerotic lesions by 40%. We conclude that an increase in eNOS activity is beneficial and provides protection against atherosclerosis.     

Elevation of plasma phospholipid transfer protein in transgenic mice increases VLDL secretion

Two lipid transfer proteins are active in human plasma, cholesteryl ester transfer protein (CETP), and phospholipid transfer protein (PLTP). Mice by nature do not express CETP. Additional inactivation of the PLTP gene resulted in reduced secretion of VLDL and subsequently in decreased susceptibility to diet-induced atherosclerosis. The aim of this study is to assess possible effects of differences in PLTP expression on VLDL secretion in mice that are proficient in CETP and PLTP. We compared human CETP transgenic (huCETPtg) mice with mice expressing both human lipid transfer proteins (huCETPtg/huPLTPtg). Plasma cholesterol in huCETPtg mice was 1.5-fold higher compared with huCETPtg/huPLTPtg mice (P < 0.001). This difference was mostly due to a lower HDL level in the huCETPtg/huPLTPtg mice, which subsequently could lead to the somewhat decreased CETP activity and concentration that was found in huCETPtg/huPLTPtg mice (P < 0.05). PLTP activity was 2.8-fold increased in these animals (P < 0.001). The human PLTP concentration was 5 microg/ml. Moderate overexpression of PLTP resulted in a 1.5-fold higher VLDL secretion compared with huCETPtg mice (P < 0.05). The composition of nascent VLDL was similar in both strains. These results indicate that elevated PLTP activity in huCETPtg mice results in an increase in VLDL secretion. In addition, PLTP overexpression decreases plasma HDL cholesterol as well as CETP.     

Fenofibrate reverses the decline in HDL cholesterol in mice overexpressing human phospholipid transfer protein

In humans, fibrates are used to treat dyslipidemia, because these drugs lower plasma triglycerides and raise HDL cholesterol. Treatment with fibrates lowers plasma phospholipid transfer protein (PLTP) activity in humans, but increases PLTP activity in mice, without a consistent effect on HDL-cholesterol concentration. Earlier, we found that PLTP overexpression in transgenic mice results in decreased plasma HDL levels and increased diet-induced atherosclerosis. So it seems that the interplay between fibrates, PLTP and HDL is different in mice and man, which may be important for atherosclerosis development. In the present study, we measured the effects of fibrates on PLTP expression in cultured human hepatocytes and effects of fibrate treatment on human PLTP expression, plasma PLTP activity and HDL levels in human PLTP transgenic mice. Fibrate treatment did not influence PLTP mRNA levels in human hepatocytes. Hepatic human PLTP mRNA levels and PLTP activity were both moderately elevated by fenofibrate treatment in human PLTP transgenic mice. In wild-type mice, however, feeding fenofibrate resulted in a strong induction of PLTP mRNA in the liver and a more than 4-fold increase of plasma PLTP activity. Plasma triglycerides were reduced in all mice by 48% or more by fenofibrate treatment. HDL-cholesterol concentrations were substantially increased by fenofibrate in PLTP overexpressing mice (+72%), but unaffected in wild-type mice. We conclude that fenofibrate treatment reverses the HDL-lowering effect of PLTP overexpression in human PLTP transgenic mice.     

Two-photon excitation fluorescence spectrum of the light-harvesting complex LH2 from Chromatium minutissimum within 650-745 nm range is determined by two-photon absorption of bacteriochlorophyll rather than of carotenoids

Two-photon fluorescence excitation spectra of the peripheral light-harvesting complex LH2 from the purple photosynthetic bacterium Chromatium minutissimum were examined within the expected spectral range of the optically forbidden S1 singlet state of carotenoids. LH2 preparations isolated from wild-type and carotenoid-depleted cells were used. 100-fs laser pulses in the range of 1300-1490 nm with an energy of 7-9 mW (corresponding to one-photon absorption between 650 and 745 nm) were used for two-photon fluorescence excitation. It was shown that two-photon fluorescence excitation spectra of LH2 complex from wild and carotenoid-depleted cells are very similar to each other and to the two-photon fluorescence excitation spectrum of bacteriochlorophyll a in acetone. It was concluded that direct two-photon excitation of bacteriochlorophyll a determines the fluorescence of both samples within the 650-745 nm spectral range.     

Identification and comparative analysis of a second runx3 promoter

Adenosine deaminase (ADA) catalyzes the hydrolysis of adenosine to inosine. Its lack determines severe combined immunodeficiency in mammals, possibly due to accumulation of extracellular adenosine, which induces apoptosis in lymphocytes (Franco et al., 1998). Thus, presence of normal levels of ADA leads to normal growth and proliferation of lymphocytes. Several vertebrate and microbial ADA amino-acid sequences are known, with substantial similarity to each other. On the other hand, there are invertebrate growth factors as well as a candidate gene for the human cat eye syndrome (CECR1) (Riazi et al., 2000. Genomics 64, 277-285), which share substantial similarity to each other, and also to ADA. In this study, we report the expression and ADA enzymatic activity of a cDNA from the salivary glands of Lutzomyia longipalpis, a blood-sucking insect, with substantial similarity to insect growth factors and to human CECR1. We also demonstrate the existence of a subfamily of the adenosine deaminase family characterized by their unique amino-terminal region. Both Drosophila melanogaster and humans have both types of adenosine deaminases. Results indicate that these invertebrate proteins previously annotated as growth factors, as well as the human CECR1 gene product, may exert their actions through adenosine depletion. The different roles played by each type of adenosine deaminase in humans and Drosophila remains to be fully investigated.     

Plasmodium malariae Infection Associated with a High Burden of Anemia: A Hospital-Based Surveillance Study

Background

Plasmodium malariae is a slow-growing parasite with a wide geographic distribution. Although generally regarded as a benign cause of malaria, it has been associated with nephrotic syndrome, particularly in young children, and can persist in the host for years. Morbidity associated with P. malariae infection has received relatively little attention, and the risk of P. malariae-associated nephrotic syndrome is unknown.

Methodology/Principal Findings

We used data from a very large hospital-based surveillance system incorporating information on clinical diagnoses, blood cell parameters and treatment to describe the demographic distribution, morbidity and mortality associated with P. malariae infection in southern Papua, Indonesia. Between April 2004 and December 2013 there were 1,054,674 patient presentations to Mitra Masyarakat Hospital of which 196,380 (18.6%) were associated with malaria and 5,097 were with P. malariae infection (constituting 2.6% of all malaria cases). The proportion of malaria cases attributable to P. malariae increased with age from 0.9% for patients under one year old to 3.1% for patients older than 15 years. Overall, 8.5% of patients with P. malariae infection required admission to hospital and the median length of stay for these patients was 2.5 days (Interquartile Range: 2.0–4.0 days). Patients with P. malariae infection had a lower mean hemoglobin concentration (9.0g/dL) than patients with P. falciparum (9.5g/dL), P. vivax (9.6g/dL) and mixed species infections (9.3g/dL). There were four cases of nephrotic syndrome recorded in patients with P. malariae infection, three of which were in children younger than 5 years old, giving a risk in this age group of 0.47% (95% Confidence Interval; 0.10% to 1.4%). Overall, 2.4% (n = 16) of patients hospitalized with P. malariae infection subsequently died in hospital, similar to the proportions for the other endemic Plasmodium species (range: 0% for P. ovale to 1.6% for P. falciparum).

Conclusions/Significance

Plasmodium malariae infection is relatively uncommon in Papua, Indonesia but is associated with significant morbidity from anemia and a similar risk of mortality to patients hospitalized with P. falciparum and P. vivax infection. In our large hospital database, one in 200 children under the age of 5 years with P. malariae infection were recorded as having nephrotic syndrome.     

Probiotics,antibiotics and the immune responses to vaccines

Orally delivered vaccines have been shown to perform poorly in developing countries. There are marked differences in the structure and the luminal environment of the gut in developing countries resulting in changes in immune and barrier function. Recent studies using newly developed technology and analytic methods have made it increasingly clear that the intestinal microbiota activate a multitude of pathways that control innate and adaptive immunity in the gut. Several hypotheses have been proposed for the underperformance of oral vaccines in developing countries, and modulation of the intestinal microbiota is now being tested in human clinical trials. Supplementation with specific strains of probiotics has been shown to have modulatory effects on intestinal and systemic immune responses in animal models and forms the basis for human studies with vaccines. However, most studies published so far that have evaluated the immune response to vaccines in children and adults have been small and results have varied by age, antigen, type of antibody response and probiotic strain. Use of anthelminthic drugs in children has been shown to possibly increase immunogenicity following oral cholera vaccination, lending further support to the rationale for modulation of the immune response to oral vaccination through the intestinal microbiome.     

Geographical spread and structural basis of sulfadoxine-pyrimethamine drug-resistant malaria parasites

The global spread of sulfadoxine (Sdx, S) and pyrimethamine (Pyr, P) resistance is attributed to increasing number of mutations in DHPS and DHFR enzymes encoded by malaria parasites. The association between drug resistance mutations and SP efficacy is complex. Here we provide an overview of the geographical spread of SP resistance mutations in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) encoded dhps and dhfr genes. In addition, we have collated the mutation data and mapped it on to the three-dimensional structures of DHPS and DHFR which have become available. Data from genomic databases and 286 studies were collated to provide a comprehensive landscape of mutational data from 2005 to 2019. Our analyses show that the Pyr-resistant double mutations are widespread in Pf/PvDHFR (P. falciparum ～61% in Asia and the Middle East, and in the Indian sub-continent; in P. vivax ～33% globally) with triple mutations prevailing in Africa (～66%) and South America (～33%). For PfDHPS, triple mutations dominate South America (～44%), Asia and the Middle East (～34%) and the Indian sub-continent (～27%), while single mutations are widespread in Africa (～45%). Contrary to the status for P. falciparum, Sdx-resistant single point mutations in PvDHPS dominate globally. Alarmingly, highly resistant quintuple and sextuple mutations are rising in Africa (PfDHFR-DHPS) and Asia (Pf/PvDHFR-DHPS). Structural analyses of DHFR and DHPS proteins in complexes with substrates/drugs have revealed that resistance mutations map proximal to Sdx and Pyr binding sites. Thus new studies can focus on discovery of novel inhibitors that target the non-substrate binding grooves in these two validated malaria parasite drug targets.     

Prevalence and correlates of poor sleep quality and daytime sleepiness in Belgian truck drivers

Sleepiness and sleep complaints are common among professional drivers. Sleepiness is a considerable problem not only because it affects the drivers' well-being, but also because of the consequences for performance and safety. Assessment of the (self-reported) prevalence and research into the risk factors are thus an important health issue and are also indispensable to prevent productivity loss and work-related accidents and injuries. Therefore, the aim of this study was to describe sleeping, driving, and health characteristics of Belgian truck drivers and to determine occupational and individual factors associated with poor sleep quality and daytime sleepiness. Cross-sectional data were collected using a self-administered questionnaire that included the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Berlin Questionnaire (BQ). The mean (SD) age of the 476 studied truck drivers was 42.7 (10.2) yrs and the mean (SD) body mass index was 27.3 (5.1) kg/m(2). Approximately 47% declared that they drove >50 h/wk and found their work schedule unrealistic. The mean (SD) PSQI score was 4.45 (2.7); poor quality of sleep (PSQI >5) was found in 27.2%. The mean (SD) ESS score was 6.79 (4.17); 18% had a score >10. The BQ indicated that 21.5% had a higher risk on obstructive sleep apnea. In multiple logistic regression analysis, low educational level (odds ratio [OR] 1.86), current smoking (OR 1.75), unrealistic work schedule (OR 1.75), and risk for obstructive sleep apnea (OR 2.97) were found to be independent correlates of daytime sleepiness. Poor sleep quality was significantly associated with poor self-perceived health (OR 1.95), unrealistic work schedule (OR 2.85), low job satisfaction (OR 1.91), and less driving experience (OR 1.73). These results show that poor sleep quality and daytime sleepiness were prevalent in Belgian truck drivers. Taking into account that several significant correlates with respect to these sleep problems were identified both at the individual and the occupational level, comprehensive countermeasures to improve working conditions and organization are needed, as well as health promotion interventions, to ensure the safety and well-being of truck drivers.