Characterization of HLA class II/peptide-TCR interactions of the immunodominant T cell epitope in Art v 1, the major mugwort pollen allergen

More than 95% of mugwort pollen-allergic individuals are sensitized to Art v 1, the major allergen in mugwort pollen. Interestingly, the CD4 T cell response to Art v 1 involves only one single immunodominant peptide, Art v 1(25-36) (KCIEWEKAQHGA), and is highly associated with the expression of HLA-DR1. Therefore, we investigated the molecular basis of this unusual immunodominance among allergens. Using artificial APC expressing exclusively HLA-DRB1*0101 and HLA-DRA*0101, we formally showed that DR1 acts as restriction element for Art v 1(25-36)-specific T cell responses. Further assessment of binding of Art v 1(25-36) to artificial HLA-DR molecules revealed that its affinity was high for HLA-DR1. Amino acid I27 was identified as anchor residue interacting with DR molecules in pocket P1. Additionally, Art v 1(25-36) bound with high affinity to HLA-DRB1*0301 and *0401, moderately to HLA-DRB1*1301 and HLA-DRB5*0101, and weakly to HLA-DRB1*1101 and *1501. T cell activation was also inducible by Art v 1(25-36)-loaded, APC-expressing HLA molecules other than DR1, indicating degeneracy of peptide binding and promiscuity of TCR recognition. Specific binding of HLA-DRB1*0101 tetramers containing Art v 1(19-36) allowed the identification of Art v 1(25-36)-specific T cells by flow cytometry. In summary, the immunodominance of Art v 1(25-36) relies on its affinity to DR1, but is not dictated by it. Future investigations at the molecular HLA/peptide/TCR and cellular level using mugwort pollen allergy as a disease model may allow new insights into tolerance and pathomechanisms operative in type I allergy, which may instigate new, T cell-directed strategies in specific immunotherapy.     

Impact on survival of intensive follow up after curative resection for colorectal cancer: systematic review and meta-analysis of randomised trials

ObjectiveTo review the evidence from clinical trials of follow up of patients after curative resection for colorectal cancer.DesignSystematic review and meta-analysis of randomised controlled trials of intensive compared with control follow up.ResultsFive trials, which included 1342 patients, met the inclusion criteria. Intensive follow up was associated with a reduction in all cause mortality (combined risk ratio 0.81, 95% confidence interval 0.70 to 0.94, P=0.007). The effect was most pronounced in the four extramural detection trials that used computed tomography and frequent measurements of serum carcinoembryonic antigen (risk ratio 0.73, 0.60 to 0.89, P=0.002). Intensive follow up was associated with significantly earlier detection of all recurrences (difference in means 8.5 months, 7.6 to 9.4 months, P<0.001) and an increased detection rate for isolated local recurrences (risk ratio 1.61, 1.12 to 2.32, P=0.011).ConclusionsIntensive follow up after curative resection for colorectal cancer improves survival. Large trials are required to identify which components of intensive follow up are most beneficial.

What is already known on this topic

There is a lack of direct evidence that intensive follow up after initial curative treatment for colorectal cancer leads to increased survivalGuidelines are inconclusive and clinical practice varies widely

What this study adds

The cumulative analysis of available data supports the view that intensive follow up after curative resection for colorectal cancer improves survivalIf computed tomography and frequent measurements of serum carcinoembryonic antigen are used during follow up mortality related to cancer is reduced by 9-13%This survival benefit is partly attributable to the earlier detection of all recurrences, particularly the increased detection of isolated recurrent disease     

Harn-steroidprofile hirsuter frauen

Urine steroid profiles of hirsute womenSteroid profiles of women suffering from idiopathic hirsutism show in more than 50% of the cases a 10–100 fold increase in the excretion of dehydroepiandrosterone (DHEA) compared with normal values.The excretion of DHEA was reduced much more than that of other 17-ketosteroids if the adrenals (NNR) were suppressed by dexamethasone (DXM). Within one week they reached values at the compound noise level of the gas chromatograms. If the ovaries were stimulated with human chorionic gonadotropin during continued suppression of the NNR with DXM no increase of DHEA could be detected.     

SALMFamide2 and serotonin immunoreactivity in the nervous system of some acoels (Xenacoelomorpha)

Acoel worms are simple, often microscopic animals with direct development, a multiciliated epidermis, a statocyst, and a digestive parenchyma instead of a gut epithelium. Morphological characters of acoels have been notoriously difficult to interpret due to their relative scarcity. The nervous system is one of the most accessible and widely used comparative features in acoels, which have a so‐called commissural brain without capsule and several major longitudinal neurite bundles. Here, we use the selective binding properties of a neuropeptide antibody raised in echinoderms (SALMFamide2, or S2), and a commercial antibody against serotonin (5‐HT) to provide additional characters of the acoel nervous system. We have prepared whole‐mount immunofluorescent stainings of three acoel species: Symsagittifera psammophila (Convolutidae), Aphanostoma pisae, and the model acoel Isodiametra pulchra (both Isodiametridae). The commissural brain of all three acoels is delimited anteriorly by the ventral anterior commissure, and posteriorly by the dorsal posterior commissure. The dorsal anterior commissure is situated between the ventral anterior commissure and the dorsal posterior commissure, while the statocyst lies between dorsal anterior and dorsal posterior commissure. S2 and serotonin do not co‐localise, and they follow similar patterns to each other within an animal. In particular, S2, but not 5‐HT, stains a prominent commissure posterior to the main (dorsal) posterior commissure. We have for the first time observed a closed posterior loop of the main neurite bundles in S. psammophila for both the amidergic and the serotonergic nervous system. In I. pulchra, the lateral neurite bundles also form a posterior loop in our serotonergic nervous system stainings.     

Zur Methodik der elektronenmikroskopischen Darstellung der Succinat-Tetrazoliumsalzreduktase mit TC-NBT

Zusammenfassung Fünf gebräuchliche Präparationsmethoden wurden auf ihre Eignung für die elektronenmikroskopische Darstellung der Succinat-Tetrazoliumsalzreduktase mit TC-NBT am Herzmuskel untersucht. Frieren und Tauen wie auch Waschen der Blöcke in Puffer vor der Inkubation in Medien mit Sacharosezusatz lieferten bei guter Strukturerhaltung spezifische Resultate. Reaktionsprodukt trat in der Innenmembran, zwischen Außen- und Innenmembran und intracristal auf. Auf einige Quellen für Fehlinterpretationen wird näher eingegangen.

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On the methods for the electron microscopic demonstration of succinate-tetrazolium salt reductase with TC-NBT

Summary Five conventional preparation methods were investigated with respect to their suitability for the electron microscopic demonstration of succinate-tetrazolium salt reductase in heart muscle. Specific results combined with satisfactory ultrastructural tissue preservation were obtained by means of freezing followed by thawing as well as by rinsing the tissue blocks in buffer solution just before incubation in saccharose-containing media. Reaction products were localized in the inner membrane and in the intermembrane and intercristal space. Some reasons for false interpretations are discussed.

     

Virus Replication, Cytopathology, and Lysosomal Enzyme Response of Mitotic and Interphase Hep-2 Cells Infected with Poliovirus

Mitotic Hep-2 cells, selected by the PEL (colloidal silica) density gradient method and held in mitosis with Colcemid, are readily infected by poliovirus type I (Mahoney). They produce and release the same amount of virus as interphase, random-growing cells. In contrast to interphase cells, mitotic cells show no detectable virus-induced cytopathic effect at the light microscopy level and only slight alterations, consisting of small clusters of vacuoles, at the electron microscopy level. Mitotic cells contain the same total amount of lysosomal enzymes per cell as interphase cells, but they display no redistribution of lysosomal enzymes during the virus infection as interphase cells do. This supports the view that lysosomal enzyme redistribution is associated with the cytopathic effect in poliovirus infection but shows that virus synthesis and release is not dependent on either the cytopathic effect or lysosomal enzyme release. The possible reasons for the lack of cytopathic effect in mitotic cells are discussed.     

Ultrastructure of spermatogenesis and mature spermatozoa in the flatworm Prosthiostomum siphunculus (Polycladida,Cotylea)

This is the first study investigating spermatogenesis and spermatozoan ultrastructure in the polyclad flatworm Prosthiostomum siphunculus. The testes are numerous and scattered as follicles ventrally between the digestive ramifications. Each follicle contains the different stages of sperm differentiation. Spermatocytes and spermatids derive from a spermatogonium and the spermatids remain connected by intercellular bridges. Chromatoid bodies are present in the cytoplasm of spermatogonia up to spermatids. During early spermiogenesis, a differentiation zone appears in the distal part of spermatids. A ring of microtubules extends along the entire sperm shaft just beneath the cell membrane. An intercentriolar body is present and gives rise to two axonemes, each with a 9 + “1” micro‐tubular pattern. Development of the spermatid leads to cell elongation and formation of a filiform, mature spermatozoon with two free flagella and with cortical microtubules along the sperm shaft. The flagella exit the sperm shaft at different levels, a finding common for acotyleans, but so far unique for cotylean polyclads. The Golgi complex produces numerous electron‐dense bodies of two types and of different sizes. These bodies are located around a perinuclear row of mitochondria. The elongated nucleus extends almost along the entire sperm body. The nucleus is wide in the proximal part and becomes narrow going towards the distal end. Thread‐like chromatin mixed with electron‐dense intranuclear spindle‐shaped bodies are present throughout nucleus. The general sperm ultrastructure, the presence of intranuclear bodies and a second type of cytoplasmic electron‐dense bodies may provide characters useful for phylogenetic analysis.