Human leukocyte antigen E in human cytomegalovirus infection: friend or foe?

Human cytomegalovirus (HCMV) is a well-studied β-herpesvirus virus, which adopts a variety of strategies to evade immune surveillance. It has been reported that in HCMV-infected cells, classical major histocompatibility (MHC) class I molecules are down-regulated, but the MHC class Ib molecule human leukocyte antigen (HLA)-E is normally expressed or even overexpressed on the cell surface. HLA-E has been first described to interact with CD94/NKG2 receptors expressed mainly on the surface of natural killer (NK) cells, thus confining its role to the regulation of NK-cell function. The engagement of CD94/NKG2A with HLA-E, with a signal peptide of the HCMV glycoprotein UL40, usually induces inhibitory signals. However, HLA-E also serves as a ligand for the TCR expressed by αβCD8(+) T cells. Recognition of peptides presented by HLA-E may result in CD8(+) effector T-cell activation. These findings will help to understand more on both pathogenic and protective roles of HLA-E in HCMV infection. In this review, we discussed recent studies about the roles of HLA-E in HCMV infection.     

Association in multifactorial traits: how to deal with rare observations?

To detect the role of a candidate gene for a trait in a sample of individuals, we may test SNP haplotype or diplotype effects. For a limited sample size, many haplotype or diplotype categories may contain few individuals. This involves a power decrease when testing the association between the trait and the haplotypes or diplotypes as these categories provide little additional information while increasing the degrees of freedom. The present paper proposes a new strategy to group rare categories based on a measure of similarity between haplotypes or diplotypes and compares it to two other possible strategies to deal with rare categories: a SNP selection strategy based on haplotype diversity, and a grouping strategy that pools all rare categories into a single baseline group. This comparison is performed by means of simulation under four scenarios. We show that this new strategy shows the largest increase in power irrespective of the model underlying the candidate gene in the studied trait. This strategy therefore provides a powerful alternative to currently used methods to reduce the number of rare categories.     

Microbiota Composition of the Intestinal Mucosa: Association with Fecal Microbiota?

The fecal and mucosal microbiota of infants with rectal bleeding and the fecal microbiota of healthy age-matched controls were investigated by fluorescent in situ hybridization. Bifidobacteria were the main genus in both the feces and mucosa. The other genera tested, Bacteroides, Clostridium, Escherichia coli and lactobacilli/enterococci, represented only minor constituents. No differences in fecal microbiota were observed between patients and controls. In the patients, however, four times greater numbers of bifidobacteria were observed in the feces when compared to the mucosa. Notwithstanding this difference, a strong positive correlation prevailed for bifidobacteria in feces and mucosal samples. The genera assessed accounted for 16% of total bacterial counts on mucosal samples and for 47% of total bacterial counts in feces. This indicates that the unidentified part of the microbiota, especially on the mucosa, deserves more attention.     

Expression of human cytomegalovirus components in the brain tissues of patients with Rasmussen’s encephalitis

Rasmussen’s encephalitis (RE) is a rare and severe progressive epileptic syndrome with unknown etiology. Infection by viruses, including human cytomegalovirus (HCMV), has been speculated to be a potential trigger for RE. However, no viral antigens have been detected in the brains of patients with RE; thus, a possible clinical linkage between viral infections and RE has not been firmly established. In this study, we evaluated the expression of HCMV pp65 antigen in brain sections from 26 patients with RE and 20 non-RE patients by immunohistochemistry and in situ hybridization, and assessed the associations between HCMV infection and clinical parameters. Elevated expression of HCMV pp65 protein and DNA was observed in 88.5% (23/26) and 69.2% (18/26) of RE cases, respectively. In the non-RE group, HCMV pp65 antigen was detected only in two cases (10%), both of which were negative for DNA staining. Additionally, the intensity of HCMV pp65 staining was correlated with a shorter duration of the prodromal stage, younger age of seizure onset, and more severe unilateral cortical atrophy. Elevated expression of HCMV pp65 was observed in RE brain tissue and was correlated with the clinical features of RE disease. In summary, our results suggested that HCMV infection may be involved in the occurrence and progression of RE disease. Thus, further studies are needed to determine whether early treatment with anti-HCMV antibodies could modulate the course of RE.

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Stabilization of Soil Organic Matter: Association with Minerals or Chemical Recalcitrance?

Soil organic matter (OM) can be stabilized against decomposition by association with minerals, by its inherent recalcitrance and by occlusion in aggregates. However, the relative contribution of these factors to OM stabilization is yet unknown. We analyzed pool size and isotopic composition (¹⁴C, ¹³C) of mineral-protected and recalcitrant OM in 12 subsurface horizons from 10 acidic forest soils. The results were related to properties of the mineral phase and to OM composition as revealed by CPMAS ¹³C-NMR and CuO oxidation. Stable OM was defined as that material which survived treatment of soils with 6 wt% sodium hypochlorite (NaOCl). Mineral-protected OM was extracted by subsequent dissolution of minerals by 10% hydrofluoric acid (HF). Organic matter resistant against NaOCl and insoluble in HF was considered as recalcitrant OM. Hypochlorite removed primarily ¹⁴C-modern OM. Of the stable organic carbon (OC), amounting to 2.4–20.6 g kg⁻¹ soil, mineral dissolution released on average 73%. Poorly crystalline Fe and Al phases (Fe_o, Al_o) and crystalline Fe oxides (Fe_d−o) explained 86% of the variability of mineral-protected OC. Atomic C_p/(Fe+Al)_p ratios of 1.3–6.5 suggest that a portion of stable OM was associated with polymeric Fe and Al species. Recalcitrant OC (0.4–6.5 g kg⁻¹ soil) contributed on average 27% to stable OC and the amount was not correlated with any mineralogical property. Recalcitrant OC had lower Δ¹⁴C and δ¹³C values than mineral-protected OC and was mainly composed of aliphatic (56%) and O-alkyl (13%) C moieties. Lignin phenols were only present in small amounts in either mineral-protected or recalcitrant OM (mean 4.3 and 0.2 g kg⁻¹ OC). The results confirm that stabilization of OM by interaction with poorly crystalline minerals and polymeric metal species is the most important mechanism for preservation of OM in these acid subsoil horizons.     

Does memory improve with age? CD85j (ILT-2/LIR-1) expression on CD8 T cells correlates with 'memory inflation' in human cytomegalovirus infection

CMV-specific memory CD8(+) T cells accumulate over time to reach high frequencies amongst peripheral blood lymphocytes - a phenomenon termed 'memory inflation'. Using tetramer staining on samples from a large number of subjects and multivariate regression analysis, we were able to relate this to the phenotype of CD8(+) T cells. We made the following observations: (i) CD85j (ILT-2/LIR-1) was highly expressed alongside CD57 - an established effector memory marker - on CMV-specific CD8(+) T cells; (ii) on CD8(+) T cells as a whole, with increasing age, CD57 and CD85j (ILT-2/LIR-1) expression increased whereas CCR7 expression decreased, indicating increasing maturation of the total CD8(+) T-cell compartment with age; (iii) unit increases in the percentage of CMV-specific CD8(+) T cells expressing CD57 and CD85j (ILT-2/LIR-1) were associated with incremental expansion of these T-cell populations; (iv) CMV seropositivity is associated with a marked effect on the overall phenotype of CD8(+) T cells (at any given age, CMV seropositivity is associated with an 18.7% increase in CD85j (ILT-2/LIR-1) expression); and (v) from our observations we estimated from this an apparent 'ageing effect' of CMV on CD8(+) T cells of 35.4 years. The data presented are consistent with a predictable, unidirectional and linear model of virus specific T-cell differentiation and maturation.     

Kaposi's Sarcoma Herpesvirus K15 Protein Contributes to Virus-Induced Angiogenesis by Recruiting PLCγ1 and Activating NFAT1-dependent RCAN1 Expression

Kaposi''s Sarcoma (KS), caused by Kaposi''s Sarcoma Herpesvirus (KSHV), is a highly vascularised angiogenic tumor of endothelial cells, characterized by latently KSHV-infected spindle cells and a pronounced inflammatory infiltrate. Several KSHV proteins, including LANA-1 (ORF73), vCyclin (ORF72), vGPCR (ORF74), vIL6 (ORF-K2), vCCL-1 (ORF-K6), vCCL-2 (ORF-K4) and K1 have been shown to exert effects that can lead to the proliferation and atypical differentiation of endothelial cells and/or the secretion of cytokines with angiogenic and inflammatory properties (VEGF, bFGF, IL6, IL8, GROα, and TNFβ). To investigate a role of the KSHV K15 protein in KSHV-mediated angiogenesis, we carried out a genome wide gene expression analysis on primary endothelial cells infected with KSHV wildtype (KSHVwt) and a KSHV K15 deletion mutant (KSHVΔK15). We found RCAN1/DSCR1 (Regulator of Calcineurin 1/Down Syndrome critical region 1), a cellular gene involved in angiogenesis, to be differentially expressed in KSHVwt- vs KSHVΔK15-infected cells. During physiological angiogenesis, expression of RCAN1 in endothelial cells is regulated by VEGF (vascular endothelial growth factor) through a pathway involving the activation of PLCγ1, Calcineurin and NFAT1. We found that K15 directly recruits PLCγ1, and thereby activates Calcineurin/NFAT1-dependent RCAN1 expression which results in the formation of angiogenic tubes. Primary endothelial cells infected with KSHVwt form angiogenic tubes upon activation of the lytic replication cycle. This effect is abrogated when K15 is deleted (KSHVΔK15) or silenced by an siRNA targeting the K15 expression. Our study establishes K15 as one of the KSHV proteins that contribute to KSHV-induced angiogenesis.     

Self or nonself? That is the question: sensing of cytomegalovirus infection by innate immune receptors

Cytomegaloviruses (CMV) are ubiquitous, opportunistic DNA viruses that have mastered the art of immune evasion through their ability to mimic host proteins or to inhibit antiviral responses. The study of the host response against CMV infection has illuminated many facets of the complex interaction between host and pathogen. Here, we review evidence derived from the animal models and human studies that supports the central role played by innate immune receptors in the recognition of virus infection and their participation in the many layers of defense.     

Physical enhancement of human performance: Is law keeping pace with science?

In the area of genometry—the nascent field of science and technology that proposes to apply enhanced understanding of the human genetic code to reshaping our individual and collective destinies—no topic has generated more interest among the general public, as well as in the athletic community, than the potential for physical enhancement of the human body and its performance. Genometric experiments have produced physically enhanced mice, and the production of similarly enhanced humans may not be far off. Although it is not the objective of most genometric research, the day will come when gene-based “treatments” will enable individuals to build muscle or increase endurance faster than is possible through conventional methods. This article describes developments in the area of physical enhancement that may find application in the “gene doping” of athletes. For example, human performance-related genes may be delivered to athletes using tools developed for research in gene therapy; the protein products of these genes may be administered in recombinant form; and recently discovered small-molecule activators of the major genetic regulatory pathways of physical prowess may be taken orally, providing “exercise in a pill”. This article also describes US and international attempts to regulate and punish the use of prohibited techniques for performance enhancement among athletes. As science advances, defining and detecting “gene doping” becomes increasingly complex. Thus, the study of physical enhancement provides an ideal starting point for the interdisciplinary Redefined Destinies Colloquium's examination of the intersection between law and science.     

African Kaposi’s Sarcoma in the Light of Global AIDS: Antiblackness and Viral Visibility

Drawing on the theoretical frameworks of antiblackness and intersectionality and the concept of viral visibility, this essay attends to the considerable archive of research about endemic Kaposi’s sarcoma (KS) in sub-Saharan Africa accrued during the mid-20th century. This body of data was inexplicably overlooked in Western research into KS during the first decade of the AIDS epidemic, during which period European and Mediterranean KS cases were most often cited as precedents despite the volume of African data available. This paper returns to the research on KS conducted in Africa during the colonial and postcolonial period to consider visibility, racial erasure, and discourses of global epidemiology, suggesting that the dynamics of medical research on HIV/AIDS have proceeded according to a tacit paradigm of antiblackness manifest in multiple exclusions of Africa from global health agendas—most recently the exclusion of the region from antiretroviral (ARV) drug therapy during the first decades of the treatment’s availability. During that decade KS all but disappeared among people with access to ARV therapy while KS became even more prevalent in sub-Saharan Africa, escalating along with HIV.     

Transformation of androgenic-derived Festulolium plants (Lolium?perenne L.?×?Festuca?pratensis Huds.) by Agrobacterium?tumefaciens

Genetic transformation of androgenic-derived amphidiploid Festulolium plants (Lolium perenne L. × Festuca pratensis Huds., 2n = 4x = 28) by Agrobacterium tumefaciens has been achieved. Anther culture-induced calli of Festulolium “Bx351” were inoculated with Agrobacterium tumefaciens strain LBA4404 carrying pIG121-Hm encoding the hygromycin resistance (hph) and β-glucuronidase (uidA) genes under the control of a CaMV 35S promoter. Twenty-three putative transformants were obtained from the hygromycin selection, 19 of which (82.6%) showed GUS activity. The integration of transgene was detected by using genomic DNA PCR analysis, RT-PCR analysis and Southern blot hybridization, respectively, which revealed that foreign gene was integrated into the genomes of dihaploid transformants (2n = 2x = 14). The haploid embryogenic system offers a stable means of transformation, as the introduced trait can be readily fixed through chromosome doubling. An erratum to this article can be found at     

Complex of human apolipoprotein C-1 with phospholipid: thermodynamic or kinetic stability?

Thermal unfolding of discoidal complexes of apolipoprotein (apo) C-1 with dimyristoyl phosphatidylcholine (DMPC) reveals a novel mechanism of lipoprotein stabilization that is based on kinetics rather than thermodynamics. Far-UV CD melting curves recorded at several heating/cooling rates from 0.047 to 1.34 K/min show hysteresis and scan rate dependence characteristic of slow nonequilibrium transitions. At slow heating rates, the apoC-1 unfolding in the complexes starts just above 25 degrees C and has an apparent melting temperature T(m) approximately 48 +/- 1.5 degrees C, close to T(m) = 51 +/- 1.5 degrees C of free protein. Thus, DMPC binding may not substantially increase the low apparent thermodynamic stability of apoC-1, DeltaG(25 degrees C) < 2 kcal/mol. The scan rate dependence of T(m) and Arrhenius analysis of the kinetic data suggest an activation enthalpy E(a) = 25 +/- 5 kcal/mol that provides the major contribution to the free energy barrier for the protein unfolding on the disk, DeltaG > or = 17 kcal/mol. Consequently, apoC-1/DMPC disks are kinetically but not thermodynamically stable. To explore the origins of this kinetic stability, we utilized dynode voltage measured in CD experiments that shows temperature-dependent contribution from UV light scattering of apoC-1/DMPC complexes (d approximately 20 nm). Correlation of CD and dynode voltage melting curves recorded at 222 nm indicates close coupling between protein unfolding and an increase in the complex size and/or lamellar structure, suggesting that the enthalpic barrier arises from transient disruption of lipid packing interactions upon disk-to-vesicle fusion. We hypothesize that a kinetic mechanism may provide a general strategy for lipoprotein stabilization that facilitates complex stability and compositional variability in the absence of high packing specificity.