Open conformers of HLA-F are high-affinity ligands of the activating NK-cell receptor KIR3DS1.

The activating natural killer (NK)-cell receptor KIR3DS1 has been linked to the outcome of various human diseases, including delayed progression of disease caused by human immunodeficiency virus type 1 (HIV-1), yet a ligand that would account for its biological effects has remained unknown. We screened 100 HLA class I proteins and found that KIR3DS1 bound to HLA-F, a result we confirmed biochemically and functionally. Primary human KIR3DS1(+) NK cells degranulated and produced antiviral cytokines after encountering HLA-F and inhibited HIV-1 replication in vitro. Activation of CD4(+) T cells triggered the transcription and surface expression of HLA-F mRNA and HLA-F protein, respectively, and induced binding of KIR3DS1. HIV-1 infection further increased the transcription of HLA-F mRNA but decreased the binding of KIR3DS1, indicative of a mechanism for evading recognition by KIR3DS1(+) NK cells. Thus, we have established HLA-F as a ligand of KIR3DS1 and have demonstrated cell-context-dependent expression of HLA-F that might explain the widespread influence of KIR3DS1 in human disease.

T cell receptors for the HIV KK10 epitope from patients with differential immunologic control are functionally indistinguishable.

HIV controllers (HCs) are individuals who can naturally control HIV infection, partially due to potent HIV-specific CD8+ T cell responses. Here, we examined the hypothesis that superior function of CD8+ T cells from HCs is encoded by their T cell receptors (TCRs). We compared the functional properties of immunodominant HIV-specific TCRs obtained from HLA-B*2705 HCs and chronic progressors (CPs) following expression in primary T cells. T cells transduced with TCRs from HCs and CPs showed equivalent induction of epitope-specific cytotoxicity, cytokine secretion, and antigen-binding properties. Transduced T cells comparably, albeit modestly, also suppressed HIV infection in vitro and in humanized mice. We also performed extensive molecular dynamics simulations that provided a structural basis for similarities in cytotoxicity and epitope cross-reactivity. These results demonstrate that the differential abilities of HIV-specific CD8+ T cells from HCs and CPs are not genetically encoded in the TCRs alone and must depend on additional factors.

scRNA-seq profiling of human granulocytes reveals expansion of developmentally flexible neutrophil precursors with mixed neutrophil and eosinophil properties in asthma.

Neutrophils and eosinophils share common hematopoietic precursors and usually diverge into distinct lineages with unique markers before being released from their hematopoietic site, which is the bone marrow (BM). However, previous studies identified an immature Ly6g(+) Il-5Rα(+) neutrophil population in mouse BM, expressing both neutrophil and eosinophil markers suggesting hematopoietic flexibility. Moreover, others have reported neutrophil populations expressing eosinophil-specific cell surface markers in tissues and altered disease states, confusing the field regarding eosinophil origins, function, and classification. Despite these reports, it is still unclear whether hematopoietic flexibility exists in human granulocytes. To answer this, we utilized single-cell RNA sequencing (scRNA-seq) and CITE-seq to profile human BM and circulating neutrophils and eosinophils at different stages of differentiation and determine whether neutrophil plasticity plays role in asthmatic inflammation. We show that immature metamyelocyte neutrophils in humans expand during severe asthmatic inflammation and express both neutrophil and eosinophil markers. We also show an increase in tri-lobed eosinophils with mixed neutrophil and eosinophil markers in allergic asthma and that IL-5 promotes differentiation of immature blood neutrophils into tri-lobed eosinophilic phenotypes suggesting a mechanism of emergency granulopoiesis to promote myeloid inflammatory or remodeling response in patients with chronic asthma. By providing insights into unexpectedly flexible granulocyte biology and demonstrating emergency hematopoiesis in asthma, our results highlight the importance of granulocyte plasticity in eosinophil development and allergic diseases.

Molecular basis of differential HLA class I-restricted T cell recognition of a highly networked HIV peptide.

Cytotoxic-T-lymphocyte (CTL) mediated control of HIV-1 is enhanced by targeting highly networked epitopes in complex with human-leukocyte-antigen-class-I (HLA-I). However, the extent to which the presenting HLA allele contributes to this process is unknown. Here we examine the CTL response to QW9, a highly networked epitope presented by the disease-protective HLA-B57 and disease-neutral HLA-B53. Despite robust targeting of QW9 in persons expressing either allele, T cell receptor (TCR) cross-recognition of the naturally occurring variant QW9_S3T is consistently reduced when presented by HLA-B53 but not by HLA-B57. Crystal structures show substantial conformational changes from QW9-HLA to QW9_S3T-HLA by both alleles. The TCR-QW9-B53 ternary complex structure manifests how the QW9-B53 can elicit effective CTLs and suggests sterically hindered cross-recognition by QW9_S3T-B53. We observe populations of cross-reactive TCRs for B57, but not B53 and also find greater peptide-HLA stability for B57 in comparison to B53. These data demonstrate differential impacts of HLAs on TCR cross-recognition and antigen presentation of a naturally arising variant, with important implications for vaccine design.

[Factors associated with Clostridium difficile disease in a tertiary-care medical institution in Mexico: a case-control study]. / Factores asociados con el desarrollo de la enfermedad por Clostridium difficile en un hospital de tercer nivel en México: estudio de casos y controles.

INTRODUCTION: Clostridium difficile-associated disease (CDAD) has been clearly associated with the use of broad-spectrum antibiotics worldwide. However, information about CDAD is scarce in Mexico and Latin America. MATERIAL AND METHODS: We studied clinical characteristics, associated factors and outcomes of all cases of CDAD diagnosed by toxin A fecal detection in a tertiary care hospital in Mexico City from 2003 to 2007. Cases were paired with controls by date of hospital discharge. RESULTS. A total of 3170 tests were performed; we evaluated 113 cases and 226 controls, with an incidence of 5.04 cases x 1000 hospital discharges during the study period. There was no difference in gender or primary diagnosis. After multivariate analysis, we found as significant risks the following: use of H2 blockers (OR 21.73, 95% CI 7.14-66.67, p < 0.001), age < 65 y (OR 10.21, IC95% 2.74-38.00, p < 0.001), prior hospitalization within 12 weeks of diagnosis (OR 4.39, IC95% 1.81-40.64, p < 0.001), prior use of cephalosporins (OR 3.41, CI 95% 1.56-7.46, p = 0.002), and fluoroquinolones (OR 3.11, IC95% 1.12-8.62, p = 0.029), stay at the intensive care unit (ICU) (OR 2.76, IC95% 1.38-5.49, p = 0.004); and, extended hospital stay (OR 1.10, IC95% 1.05-1.16, p < 0.001) or antimicrobial use before diagnosis (OR 1.05, IC95% 1.01-1.09, p = 0.010). We described an outbreak of 12 cases occurred in August of 2005 (29.5 cases per 1,000 discharges). We also observed a higher seasonal incidence of disease during the summer in the study period. CONCLUSIONS: The use of H2 blockers, age < 65 years, prior hospitalization or earlier use of cephalosporins or fluoroquinolones, as well as stay at the ICU were independent risk factor for CDAD.

HIV Controllers Exhibit Effective CD8+ T Cell Recognition of HIV-1-Infected Non-activated CD4+ T Cells.

Even with sustained antiretroviral therapy, resting CD4+ T cells remain a persistent reservoir of HIV infection, representing a critical barrier to curing HIV. Here, we demonstrate that CD8+ T cells recognize infected, non-activated CD4+ T cells in the absence of de novo protein production, as measured by immune synapse formation, degranulation, cytokine production, and killing of infected cells. Immune recognition is induced by HLA-I presentation of peptides derived from incoming viral particles, and recognition occurred either following cell-free virus infection or following cell-to-cell spread. CD8+ T cells from HIV controllers mediate more effective immune recognition than CD8+ T cells from progressors. These results indicate that non-activated HIV-infected CD4+ T cells can be targeted by CD8+ T cells directly after HIV entry, before reverse transcription, and thus before the establishment of latency, and suggest a mechanism whereby the immune response may reduce the size of the HIV reservoir.

[Value of the assessment of myocardial viability: evaluation with positron emission tomography 18F-FDG]. / Importancia de la detección de viabilidad miocárdica: evaluación con tomografía por emisión de positrones con 18F-FDG.

It used to be thought that the consequences of coronary artery disease were final, and that the prognosis of the patient was limited to the extent of the ventricular dysfunction. This paradigm changed radically when the concept of hibernating myocardium was introduced, which states the existence of tissue that can regain contractile function after being re-vascularized. This introduced a new concept in cardiology: myocardial viability. This work presents a clear example of the importance of detecting myocardial viability in selected patients, due to the impact not only in treatment but in prognosis as well. It is also emphasized that positron emission tomography (PET) is the gold standard method to detect myocardial viability.

A genome-wide CRISPR screen identifies a restricted set of HIV host dependency factors.

Host proteins are essential for HIV entry and replication and can be important nonviral therapeutic targets. Large-scale RNA interference (RNAi)-based screens have identified nearly a thousand candidate host factors, but there is little agreement among studies and few factors have been validated. Here we demonstrate that a genome-wide CRISPR-based screen identifies host factors in a physiologically relevant cell system. We identify five factors, including the HIV co-receptors CD4 and CCR5, that are required for HIV infection yet are dispensable for cellular proliferation and viability. Tyrosylprotein sulfotransferase 2 (TPST2) and solute carrier family 35 member B2 (SLC35B2) function in a common pathway to sulfate CCR5 on extracellular tyrosine residues, facilitating CCR5 recognition by the HIV envelope. Activated leukocyte cell adhesion molecule (ALCAM) mediates cell aggregation, which is required for cell-to-cell HIV transmission. We validated these pathways in primary human CD4+ T cells through Cas9-mediated knockout and antibody blockade. Our findings indicate that HIV infection and replication rely on a limited set of host-dispensable genes and suggest that these pathways can be studied for therapeutic intervention.

[Beta-1 adrenoceptor blockade decreases the firing rate to painful stimuli in spinal wide-dynamic range neurons in rats]. / Los bloqueadores beta-1 adrenérgicos reducen la respuesta a estímulos dolorosos en neuronas de amplio rango dinámico de la médula espinal en ratas.

BACKGROUND: It is known that epinephrine/norepinephrine inhibit acute pain transmission. However, the role of ß-adrenoceptors is not clear. Thus, we analyzed if beta-1 and/or beta-2 adrenoceptors can modulate acute pain transmission by performing in vivo single unit recordings during painful and non-painful peripheral stimulation in rats. METHODS: Longitudinal study in which we analyzed seven groups of male rats Wistar: control group (n = 11): saline (0.9 %); EPI group (n = 8): epinephrine 100 mcg; beta-1 agonist group (n = 8): dobutamine 125 mcg; beta-1-antagonist group (n = 9): metoprolol 100 mcg; beta-2-agonist group (n = 7): clenbuterol 100 mcg; beta-2-antagonist group (n = 8): butoxamine 100 mcg; beta-1-antagonist + EPI group (n = 10): metoprolol 100 mcg + epinephrine 100 mcg. For the statistical analysis we used ANOVA. RESULTS: Epinephrine significantly reduced the basal firing rate (BFR) in 34.1 % (p < 0.05) and also the evoked response by painful stimulation in 56 % (p < 0.05). No change was observed in the evoked response by non-painful stimulation. ANTß1 was the only beta-adrenoceptor acting drug that significantly reduced the evoked response by painful stimulation in 41 % (p < 0.05). None of the other drugs alone affected either the BFR or the evoked response to non-painful or painful stimulation. CONCLUSIONS: It is the first time that a beta-1-adrenoceptor antagonist (metoprolol) probes to be effective in reducing the response to painful stimulation in WDR neurons.

Introducción: la epinefrina/norepinefrina inhibe la transmisión del dolor agudo; empero, no es claro el papel de los receptores beta-adrenérgicos. Por tanto, analizamos si los fármacos de estos receptores modulan la transmisión del dolor agudo mediante registro electrofisiológico unitario extracelular in vivo durante estimulación periférica dolorosa y no dolorosa en ratas. Métodos: estudio longitudinal en el que se cotejaron siete grupos de ratas: control (n = 11): solución salina (0,9 %); EPI (n = 8): 100 mcg epinefrina; agonista beta-1 (n = 8): 125 mcg dobutamina; antagonista beta-1 (n = 9): 100 mcg metoprolol; agonista beta-2 (n = 7): 100 mcg clembuterol; antagonista beta-2 (n = 8): butoxamina 100 mcg; antagonista beta-1 + EPI (n = 10): 100 mcg metoprolol + 100 mcg epinefrina. Se hizo análisis estadístico por medio de ANOVA. Resultados: La epinefrina redujo significativamente la tasa de disparo basal (RDB) en 34.1 % (p < 0.05) y la respuesta evocada por la estimulación dolorosa en 56 % (p < 0.05). No hubo cambios en la respuesta provocada por la falta de estimulación dolorosa. El antagonista beta-1 fue el único fármaco con acción beta-adrenérgica que redujo significativamente la respuesta evocada por la estimulación dolorosa en 41 % (p < 0.05). Conclusión: por primera vez un antagonista de los receptores beta-1-adrenérgicos (metoprolol) prueba ser eficaz en la reducción de la respuesta a la estimulación dolorosa en las neuronas ARD.

[The impact of detecting endothelial dysfunction in atherosclerosis: Role of positron emission tomography (PET)]. / El impacto de la detección de disfunción endotelial en la aterosclerosis: estudio mediante tomografía por emisión de positrones.

The endothelium plays an important role in the regulation of the intracellular fluid, vascular permeability, and modulation of vascular focal tone and angiogenesis. Endothelial dysfunction is manifested by the loss of the endothelium ability to modulate physiology changes in its vascular bed, and actually it is considered a prognostic marker of coronary artery disease. The relevance of assessing endothelial dysfunction relies in that it has been observed in different pathologies like DM, dyslipidemia, hypertension, tabaquism and in immunologic diseases like antiphospholipid syndrome and systemic lupus. PET is a non invasive method that allows the absolute quantification of myocardial blood flow during rest, stress and adrenergic stimulation, which allows to asses endothelial function. Therefore PET is a useful diagnostic technique to identify patients with endothelial dysfunction, and in the assessment of its response to administered therapy, allowing an optimal control and prevention of secondary adverse events of these diseases.

El impacto de la detección de disfunción endotelial en la aterosclerosis: estudio mediante tomografía por emisión de positrones / Impact of the detection of endothelial dysfunction in atherosclerosis: Assessment by positron emission tomography

El endotelio juega un papel importante en la regulación del líquido intracelular, la permeabilidad vascular, en la modulación del tono vascular focal y la angiogénesis. La disfunción endotelial se manifiesta por la pérdida de la capacidad del endotelio de modular el comportamiento fisiológico del lecho vascular y actualmente se considera un marcador pronóstico de la enfermedad arterial coronaria. La relevancia de estudiar la disfunción endotelial radica en que ésta se ha observado en diversas patologías como diabetes mellitas (DM), dislipidemia, hipertensión arterial sistémica, tabaquismo o en enfermedades inmunológicas como síndrome antifosfolípido y lupus eritematoso sistémico. La Tomografía por Emisión de Positrones (PET) es un método no invasivo que permite cuantificar en términos absolutos el flujo miocárdico en reposo, esfuerzo y durante la estimulación adrenérgica, siendo considerado en la actualidad el estándar de oro para valorar la función endotelial. Por lo tanto el PET es una herramienta diagnóstica muy útil en identificar a los pacientes con disfunción endotelial y en evaluar la respuesta a la terapia administrada en enfermedades que se acompañen de ésta. Permitiendo un control óptimo y prevención de eventos adversos de estas enfermedades.

The endothelium plays an important role in the regulation of the intracellular fluid, vascular permeability, and modulation of vascular focal tone and angiogenesis. Endothelial dysfunction is manifested by the loss of the endothelium ability to modulate physiology changes in its vascular bed, and actually it is considered a prognostic marker of coronary artery disease. The relevance of assessing endothelial dysfunction relies in that it has been observed in different pathologies like DM, dyslipidemia, hypertension, tabaquism and in immunologic diseases like antiphospholipid syndrome and systemic lupus. PET is a non invasive method that allows the absolute quantification of myocardial blood flow during rest, stress and adrenergic stimulation, which allows to asses endothelial function. Therefore PET is a useful diagnostic technique to identify patients with endothelial dysfunction, and in the assessment of its response to administered therapy, allowing an optimal control and prevention of secondary adverse events of these diseases.

Importancia de la detección de viabilidad miocárdica: evaluación con tomografía por emisión de positrones con 18F-FDG / Value of the assessment of myocardial viability: evaluation with positron emission tomography 18F-FDG

It used to be thought that the consequences of coronary artery disease were final, and that the prognosis of the patient was limited to the extent of the ventricular dysfunction. This paradigm changed radically when the concept of hibernating myocardium was introduced, which states the existence of tissue that can regain contractile function after being re-vascularized. This introduced a new concept in cardiology: myocardial viability. This work presents a clear example of the importance of detecting myocardial viability in selected patients, due to the impact not only in treatment but in prognosis as well. It is also emphasized that positron emission tomography (PET) is the gold standard method to detect myocardial viability.