New Constraint on the Local Relic Neutrino Background Overdensity with the First KATRIN Data Runs

We report on the direct search for cosmic relic neutrinos using data acquired during the first two science campaigns of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the end point at 18.57 keV. The analysis is sensitive to a local relic neutrino overdensity ratio of η<9.7×10^{10}/α (1.1×10^{11}/α) at a 90% (95%) confidence level with α=1 (0.5) for Majorana (Dirac) neutrinos. A fit of the integrated electron spectrum over a narrow interval around the end point accounting for relic neutrino captures in the tritium source reveals no significant overdensity. This work improves the results obtained by the previous neutrino mass experiments at Los Alamos and Troitsk. We furthermore update the projected final sensitivity of the KATRIN experiment to η<1×10^{10}/α at 90% confidence level, by relying on updated operational conditions.

Bound on 3+1 Active-Sterile Neutrino Mixing from the First Four-Week Science Run of KATRIN

We report on the light sterile neutrino search from the first four-week science run of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are analyzed by a high-resolution MAC-E filter down to 40 eV below the endpoint at 18.57 keV. We consider the framework with three active neutrinos and one sterile neutrino. The analysis is sensitive to the mass, m_{4}, of the fourth mass state for m_{4}^{2}≲1000  eV^{2} and to active-to-sterile neutrino mixing down to |U_{e4}|^{2}≳2×10^{-2}. No significant spectral distortion is observed and exclusion bounds on the sterile mass and mixing are reported. These new limits supersede the Mainz results for m_{4}^{2}≲1000  eV^{2} and improve the Troitsk bound for m_{4}^{2}<30  eV^{2}. The reactor and gallium anomalies are constrained for 100<Δm_{41}^{2}<1000  eV^{2}.

Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of (-1.0_{-1.1}^{+0.9})  eV^{2}. From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of 2 and provides model-independent input to cosmological studies of structure formation.

Sequence conservation predicts T cell reactivity against ragweed allergens

BACKGROUND

Ragweed is a major cause of seasonal allergy, affecting millions of people worldwide. Several allergens have been defined based on IgE reactivity, but their relative immunogenicity in terms of T cell responses has not been studied.

OBJECTIVE

We comprehensively characterized T cell responses from atopic, ragweed-allergic subjects to Amb a 1, Amb a 3, Amb a 4, Amb a 5, Amb a 6, Amb a 8, Amb a 9, Amb a 10, Amb a 11, and Amb p 5 and examined their correlation with serological reactivity and sequence conservation in other allergens.

METHODS

Peripheral blood mononuclear cells (PBMCs) from donors positive for IgE towards ragweed extracts after in vitro expansion for secretion of IL-5 (a representative Th2 cytokine) and IFN-γ (Th1) in response to a panel of overlapping peptides spanning the above-listed allergens were assessed.

RESULTS

Three previously identified dominant T cell epitopes (Amb a 1 176-191, 200-215, and 344-359) were confirmed, and three novel dominant epitopes (Amb a 1 280-295, 304-319, and 320-335) were identified. Amb a 1, the dominant IgE allergen, was also the dominant T cell allergen, but dominance patterns for T cell and IgE responses for the other ragweed allergens did not correlate. Dominance for T cell responses correlated with conservation of ragweed epitopes with sequences of other well-known allergens.

CONCLUSIONS AND CLINICAL RELEVANCE

These results provide the first assessment of the hierarchy of T cell reactivity in ragweed allergens, which is distinct from that observed for IgE reactivity and influenced by T cell epitope sequence conservation. The results suggest that ragweed allergens associated with lesser IgE reactivity and significant T cell reactivity may be targeted for T cell immunotherapy, and further support the development of immunotherapies against epitopes conserved across species to generate broad reactivity against many common allergens.

Definition of a pool of epitopes that recapitulates the T cell reactivity against major house dust mite allergens

BACKGROUND

Allergens from house dust mites (HDM) are a common cause of asthma. Der p and Der f from Dermatophagoides sp. are strong immunogens in humans. Allergen extracts are used to study T helper (Th2) cell responses to HDM, which are implicated in the development and regulation of allergic disease.

OBJECTIVE

To define an epitope mixture that recapitulates, and might substitute for, HDM extract in terms of detecting and characterizing Th2 cell responses.

METHODS

Peripheral blood mononuclear cells (PBMC) from 52 HDM allergic and 10 non-allergic individuals were stimulated with HDM extracts and assayed with a set of 178 peptides spanning mite allergens group Der p 1, 2, 23 and Der f group 1 and 2 allergens. A pool of the most dominant T cell epitopes identified in the present study and from published literature was assembled and tested for ex vivo T cell responses. Correlation with HDM-specific IgE titres was examined.

RESULTS

Patterns of T cell reactivity to Der p and Der f - derived peptides revealed a large number of epitopes. Clear patterns of immunodominance were apparent, with HDM allergen group 1 and 2 dominant over group 23. Furthermore, within a given antigen, 6-11 epitopes accounted for the vast majority of responses. Based on these results and published data, a comprehensive dust mite pool (DMP) of epitopes was designed and found to allow detection of ex vivo T cell responses. DMP ex vivo reactivity correlated with HDM-specific IgE titres and was similar to that detected with commonly used HDM extracts. Ex vivo DMP stimulation was associated with a predominant Th2 response in allergic donors, and minor reactivity of T cells producing IFNγ, IL17 and IL10.

CONCLUSIONS & CLINICAL RELEVANCE

A detailed map of Der p and Der f antigens defined a pool of epitopes that can be used to detect ex vivo HDM responses.

Maternal and newborn vitamin D status and its impact on food allergy development in the German LINA cohort study

BACKGROUND

Vitamin D levels are known to be associated with atopic disease development; however, existing data are controversial. The aim of this study was to investigate whether corresponding maternal and cord blood vitamin D levels are associated with atopic outcomes in early infancy.

METHODS

Within the LINA cohort study (Lifestyle and environmental factors and their Influence on Newborns Allergy risk), 25(OH)D was measured in blood samples of 378 mother-child pairs during pregnancy and at birth. Information about children's atopic manifestations during the first 2 years of life was obtained from questionnaires filled out by the parents during pregnancy and annually thereafter. Cord blood regulatory T cells (Treg) were detected by methylation-specific PCR using a Treg-specific demethylated region in the FOXP3 gene.

RESULTS

The median maternal 25(OH)D(3) level was 22.19 ng/ml (IQR 14.40-31.19 ng/ml); the median cord blood 25(OH)D(3) 10.95 ng/ml (6.99-17.39 ng/ml). A high correlation was seen between maternal and cord blood 25(OH)D(3) levels, both showing a seasonal distribution. Maternal and cord blood 25(OH)D(3) was positively associated with children's risk for food allergy within the first 2 years. Further, higher maternal 25(OH)D(3) resulted in a higher risk for sensitization against food allergens at the age of two. Cord blood 25(OH)D(3) levels were negatively correlated with regulatory T cell numbers.

CONCLUSION

Our study demonstrates that high vitamin D levels in pregnancy and at birth may contribute to a higher risk for food allergy and therefore argues against vitamin D supplement to protect against allergy.

Cord blood Tregs with stable FOXP3 expression are influenced by prenatal environment and associated with atopic dermatitis at the age of one year

BACKGROUND

Regulatory T cells (Tregs) with stable FOXP3 expression are characterized by a specific demethylated region in the FOXP3 gene (Treg-specific demethylated region, TSDR). The aim of this study was to analyse the influence of prenatal factors on cord blood Treg numbers, as detected by changes in the TSDR demethylation, and the subsequent risk for allergic diseases.

METHODS

Analyses were performed within the LINA study in blood samples from pregnant women (34th gestational week) and in cord blood (n = 346 mother-child pairs). Treg numbers were detected via DNA demethylation in the FOXP3 TSDR. At age 1, total and specific IgE was measured in children's blood. In addition, maternal cytokine production (Th1/Th2/Th17) was analysed. Exposure and disease outcomes were assessed by questionnaires.

RESULTS

Boys had lower Treg numbers compared with girls (P < 0.001). Parental atopy history, particularly maternal hay fever and paternal asthma were related to lower Treg numbers in cord blood (adj. MR = 0.81, 95% CI = 0.68-0.97; adj. MR = 0.60, 95% CI = 0.45-0.81). Maternal cytokines (IL-13, IL-17E and IFN-γ) and maternal smoking/exposure to tobacco smoke during pregnancy were also associated with decreased cord blood Treg numbers (adj. MR = 0.89, 95% CI = 0.97-1.00). Children with lower Treg numbers at birth had a higher risk to develop atopic dermatitis (adj. OR = 1.55, 95% CI = 1.00-2.41) and sensitization to food allergens (adj. OR = 1.55, 95% CI = 1.06-2.25) during the first year of life.

CONCLUSIONS

These results indicate that both genetic and environmental factors presumably influence the development of foetal Tregs. Low cord blood Treg numbers may predict early atopic dermatitis.

Maternal immune status in pregnancy is related to offspring's immune responses and atopy risk

BACKGROUND

The influence of maternal immune responses in pregnancy on children's immune competence and the development of atopic diseases later in life are poorly understood. To determine potential maternal effects on the maturation of children's immune system and resulting disease risks, we analysed immune responses in mother-child pairs in a prospective birth cohort study.

METHODS

Within the Lifestyle and Environmental factors and their Influence on Newborns Allergy risk (LINA) study, concentrations of Th1/Th2/Th17 and inflammatory cytokines/chemokines as well as IgE were measured in phytohemagglutinin and lipopolysaccharide stimulated maternal blood in the 34th week of gestation and in corresponding children's blood at birth and 1 year after (n = 353 mother-child pairs). Information on atopic outcomes during the first year of life was obtained from questionnaires.

RESULTS

Concentrations of inflammatory markers, excepting TNF-α, were manifold higher in cord blood samples compared with maternal blood. Th1/Th2 cytokines were lower in children's blood with a Th2 bias at birth. Maternal inflammatory parameters (MCP-1, IL-10, TNF-α) in pregnancy showed an association with corresponding cytokines blood levels in children at the age of one. High maternal IgE concentrations in pregnancy were associated with increased children's IgE at birth and at the age of one, whereas children's atopic dermatitis (AD) was determined by maternal AD.

CONCLUSIONS

Maternal inflammatory cytokines during pregnancy correlate with children's corresponding cytokines at the age of one but are not related to IgE or AD. While maternal IgE predicts children's IgE, AD in children is only associated with maternal disease.

Reduced maternal regulatory T cell numbers and increased T helper type 2 cytokine production are associated with elevated levels of immunoglobulin E in cord blood

BACKGROUND

There is evidence that the basis of an atopic-skewed immune response is acquired early in life, perhaps at the fetal stage. Thus, we hypothesized that the development of the fetal immune system might be influenced by maternal regulatory T cells (Treg) and maternal T cell cytokine production during pregnancy. The aim of the present study was to assess the influence of maternal Treg and cytokine production during pregnancy on Treg and atopy at birth.

METHODS

Within the mother-child study LINA (Lifestyle and Environmental factors and their Influence on Newborns Allergy risk), we determined the frequency and function of Treg and the total IgE concentration in pregnant women in the 34th week of gestation and in corresponding cord bloods at birth (n=24). Furthermore, we assessed how maternal mitogen-induced T-helper type 1/T-helper type 2 and inflammatory cytokines influence the level of cord blood Treg and IgE.

RESULTS

Frequencies of CD4(+)CD25(high) T cells were higher (P=0.001), whereas percentages of FOXP3+ T cells were lower (P<0.001) in cord blood cells compared with maternal blood. Reduced maternal CD4(+)CD25(high) Treg frequencies correlated with increased total IgE concentrations at the 34th week of gestation (r=-0.32, P=0.028) and with increased IgE concentrations in cord blood (r=-0.50, P<0.001). Elevated maternal mitogen-induced Th2 cytokine production was related to increased total IgE levels in the serum of corresponding cord bloods (IL-4, r=0.53; IL-5, r=0.43; IL-13, r=0.52).

CONCLUSIONS

Because cord blood IgE has been shown to be predictive for allergic diseases in early childhood, our results indicate that reduced maternal Treg numbers and increased Th2 cytokine production during pregnancy might influence the allergy risk of the child.

Solid-phase micro extraction (SPME) and headspace derivatization of clenbuterol followed by GC-FID and GC-SIMMS quantification

Solid-phase micro extraction (SPME) and on-fiber derivatization followed by Gas Chromatography coupled with Flame Ionization Detection (GC-FID) or Selected Ion Monitoring Mass Spectrometry (GC-SIMMS) allows for simple yet sensitive quantification for the hexamethyldisilazane derivative of the beta-agonist clenbuterol. Using an 85- micro m polyacrylate fiber, the analysis method is optimized with respect to extraction time, derivatization time and temperature, and solution pH. In addition, the use of a rapid temperature ramping injection port allows for optimization of fiber desorption conditions. Under optimal conditions, the limits of detection for the hexamethyldisilazane derivative of clenbuterol are 1.1 ppb by FID and 0.20 ppb by SIMMS.

Structure and mesomorphism of neodymium(III) alkanoates

The structural and thermal behavior of all members of the homologous series of neodymium(III) alkanoates, ranging from neodymium(III) butyrate to neodymium(III) eicosanoate are described. Neodymium(III) butyrate monohydrate, Nd(C3H7COO)3.H2O crystallizes in space group P1 (No. 2), Z = 2. The lattice parameters are a = 9.824(2) A, b = 11.974(2) A, c = 14.633(2) A, alpha = 86.21(2) degrees, beta = 75.92(2) degrees, gamma = 77.97(2) degrees. The crystal structure consists of ionic layers of neodymium ions, separated by bilayers of butyrate anions. In the ionic layers, the neodymium ions are connected by bridging tridentate carboxylate groups to zigzag chains, whereas the chains are connected among themselves by bridging bidentate carboxylate groups. The two crystallographically different neodymium ions are both having coordination number 9, with a geometry close to a monocapped square antiprism. The structure of the higher homologues can be derived from the structure of neodymium butyrate by extending the alkyl chains. These compounds have a lamellar bilayer structure with planes of neodymium(III) ions coordinated to the carboxylate groups and with the alkyl chains in an all-trans conformation. All homologous compounds from neodymium(III) pentanoate to neodymium(III) pentadecanoate display a thermotropic mesophase, which was identified by high-temperature X-ray diffraction as a smectic A phase. For the series from neodymium(III) pentanoate to neodymium(III) undecanoate an additional high viscosity mesophase is present between the crystalline state and the smectic A mesophase.

Epidermal G1-chalone and transforming growth factor-beta are two different endogenous inhibitors of epidermal cell proliferation

Epidermal G1-chalone and transforming growth factor-beta (TGF beta), two endogenous inhibitors of epidermal cell proliferation, were compared with regard to several effects on epidermis in vivo and in vitro. Both factors inhibited DNA labeling in a rat tongue epithelial cell line, with similar kinetics and half-maximal effects at approximately 1 pg/ml (enriched chalone) and 1 ng/ml (TGF beta). For primary neonatal mouse keratinocytes, TGF beta was found to be a rather strong inhibitor of cell proliferation, whereas chalone showed only a weak effect on cells grown in medium containing 1.2 mM Ca2+ and no effect at all in the presence of 0.06 mM Ca2+. Vice versa, upon i.p. injection, only chalone was able to inhibit mouse epidermal DNA synthesis in vivo, whereas TGF beta had no effect at all. A moderate increase of transglutaminase activity in neonatal primary mouse keratinocytes was induced by both factors at concentrations of about 300 pg TGF beta/ml and 10 pg chalone fraction/ml. Chalone did not compete with [125I]TGF beta for specific binding sites on primary murine keratinocytes. A polyclonal "chalone antiserum" did not interact with TGF beta, and a neutralizing TGF beta antibody that inhibited the effect of TGF beta on cell proliferation could not block the inhibitory effect of chalone on RTE2 cells. In contrast to TGF beta, epidermal G1-chalone did not induce proliferation of NIH-3T3 cells. These results indicate that epidermal G1-chalone and TGF beta are two different inhibitors of epidermal cell proliferation.