In Vitro Induction of Human Regulatory T Cells Using Conditions of Low Tryptophan Plus Kynurenines.

Thymic regulatory T cells (tTregs) and induced regulatory T cells (iTregs) suppress murine acute graft-versus-host disease (GVHD). Previously, we demonstrated that the plasmacytoid dendritic cell indoleamine 2,3-dioxygenase (IDO) fosters the in vitro development of human iTregs via tryptophan depletion and kynurenine (Kyn) metabolites. We now show that stimulation of naïve CD4+ T cells in low tryptophan (low Trp) plus Kyn supports human iTreg generation. In vitro, low Trp + Kyn iTregs and tTregs potently suppress T effector cell proliferation equivalently but are phenotypically distinct. Compared with tTregs or T effector cells, bioenergetics profiling reveals that low Trp + Kyn iTregs have increased basal glycolysis and oxidative phosphorylation and use glutaminolysis as an energy source. Low Trp + Kyn iTreg viability was reliant on interleukin (IL)-2 in vitro. Although in vivo IL-2 administration increased low Trp + Kyn iTreg persistence on adoptive transfer into immunodeficient mice given peripheral blood mononuclear cells to induce GVHD, IL-2-supported iTregs did not improve recipient survival. We conclude that low Trp + Kyn create suppressive iTregs that have high metabolic needs that will need to be addressed before clinical translation.

IL-15 super-agonist (ALT-803) enhances natural killer (NK) cell function against ovarian cancer.

OBJECTIVE: Natural killer (NK) cells represent a powerful immunotherapeutic target as they lyse tumors directly, do not require differentiation, and can elicit potent inflammatory responses. The objective of these studies was to use an IL-15 super-agonist complex, ALT-803 (Altor BioScience Corporation), to enhance the function of both normal and ovarian cancer patient derived NK cells by increasing cytotoxicity and cytokine production. METHODS: NK cell function from normal donor peripheral blood mononuclear cells (PBMCs) and ovarian cancer patient ascites was assessed using flow cytometry and chromium release assays ±ALT-803 stimulation. To evaluate the ability of ALT-803 to enhance NK cell function in vivo against ovarian cancer, we used a MA148-luc ovarian cancer NOD scid gamma (NSG) xenogeneic mouse model with transferred human NK cells. RESULTS: ALT-803 potently enhanced functionality of NK cells against all ovarian cancer cell lines with significant increases seen in CD107a, IFNγ and TNFα expression depending on target cell line. Function was also rescued in NK cells derived from ovarian cancer patient ascites. Finally, only animals treated with intraperitoneal ALT-803 displayed an NK dependent significant decrease in tumor. CONCLUSIONS: ALT-803 enhances NK cell cytotoxicity against ovarian cancer in vitro and in vivo and is able to rescue functionality of NK cells derived from ovarian cancer patient ascites. These findings suggest that ALT-803 has the potential to enhance NK cell-based immunotherapeutic approaches for the treatment of ovarian cancer.

Breast cancer risk and protracted low-to-moderate dose occupational radiation exposure in the US Radiologic Technologists Cohort, 1983-2008.

BACKGROUND: Although high-dose ionising radiation is associated with increased breast cancer risks, the association with protracted low-dose-rate exposures remains unclear. The US Radiologic Technologist study provides an opportunity to examine the association between low-to-moderate dose radiation and breast cancer incidence and mortality. METHODS: One thousand nine hundred and twenty-two self-reported first primary cancers were diagnosed during 1983-2005 among 66 915 female technologists, and 586 breast cancer deaths occurred during 1983-2008 among 83 538 female cohort members. Occupational breast dose estimates were based on work histories, historical data, and, after the mid-1970s, individual film badge measurements. Excess relative risks were estimated using Poisson regression with birth cohort stratification and adjustment for menopause, reproductive history, and other risk factors. RESULTS: Higher doses were associated with increased breast cancer incidence, with an excess relative risk at 100 mGy of 0.07 (95% confidence interval (CI): -0.005 to 0.19). Associations were strongest for technologists born before 1930 (excess relative risk at 100 mGy=0.16; 95% CI: 0.03-0.39) with similar patterns for mortality among technologists born before 1930. CONCLUSIONS: Occupational radiation to the breast was positively associated with breast cancer risk. The risk was more pronounced for women born before 1930 who began working before 1950 when mean annual doses (37 mGy) were considerably higher than in later years (1.3 mGy). However, because of the uncertainties and possible systematic errors in the occupational dose estimates before 1960, these findings should be treated with caution.

Tissue vascularization through 3D printing: Will technology bring us flow?

BACKGROUND: Though in vivo models provide the most physiologically relevant environment for studying tissue function, in vitro studies provide researchers with explicit control over experimental conditions and the potential to develop high throughput testing methods. In recent years, advancements in developmental biology research and imaging techniques have significantly improved our understanding of the processes involved in vascular development. However, the task of recreating the complex, multi-scale vasculature seen in in vivo systems remains elusive. RESULTS: 3D bioprinting offers a potential method to generate controlled vascular networks with hierarchical structure approaching that of in vivo networks. Bioprinting is an interdisciplinary field that relies on advances in 3D printing technology along with advances in imaging and computational modeling, which allow researchers to monitor cellular function and to better understand cellular environment within the printed tissue. CONCLUSIONS: As bioprinting technologies improve with regards to resolution, printing speed, available materials, and automation, 3D printing could be used to generate highly controlled vascularized tissues in a high throughput manner for use in regenerative medicine and the development of in vitro tissue models for research in developmental biology and vascular diseases.

Characterization of a weakly expressed KIR2DL1 variant reveals a novel upstream promoter that controls KIR expression.

Members of the human KIR (killer cell immunoglobulin-like receptor) class I major histocompatibility complex receptor gene family contain multiple promoters that determine the variegated expression of KIR on natural killer cells. In order to identify novel genetic alterations associated with decreased KIR expression, a group of donors was characterized for KIR gene content, transcripts and protein expression. An individual with a single copy of the KIR2DL1 gene but a very low level of gene expression was identified. The low expression phenotype was associated with a single-nucleotide polymorphism (SNP) that created a binding site for the inhibitory ZEB1 (Zinc finger E-box-binding homeobox 1) transcription factor adjacent to a c-Myc binding site previously implicated in distal promoter activity. Individuals possessing this SNP had a substantial decrease in distal KIR2DL1 transcripts initiating from a novel intermediate promoter located 230 bp upstream of the proximal promoter start site. Surprisingly, there was no decrease in transcription from the KIR2DL1 proximal promoter. Reduced intermediate promoter activity revealed the existence of alternatively spliced KIR2DL1 transcripts containing premature termination codons that initiated from the proximal KIR2DL1 promoter. Altogether, these results indicate that distal transcripts are necessary for KIR2DL1 protein expression and are required for proper processing of sense transcripts from the bidirectional proximal promoter.

Identification of a KIR antisense lncRNA expressed by progenitor cells.

Human NK cells express cell surface class I MHC receptors (killer cell immunoglobulin-like receptor, KIR) in a probabilistic manner. Previous studies have shown that a distal promoter acts in conjunction with a proximal bidirectional promoter to control the selective activation of KIR genes. We report here the presence of an intron 2 promoter in several KIR genes that produce a spliced antisense transcript. This long noncoding RNA (lncRNA) transcript contains antisense sequence complementary to KIR-coding exons 1 and 2 as well as the proximal promoter region of the KIR genes. The antisense promoter contains myeloid zinc finger 1 (MZF-1)-binding sites, a transcription factor found in hematopoietic progenitors and myeloid precursors. The KIR antisense lncRNA was detected only in progenitor cells or pluripotent cell lines, suggesting a function that is specific for stem cells. Overexpression of MZF-1 in developing NK cells led to decreased KIR expression, consistent with a role for the KIR antisense lncRNA in silencing KIR gene expression early in development.

Prevalence and Impact of SDHI Fungicide Resistance in Alternaria solani.

Early blight, caused by Alternaria solani, is an important chronic foliar disease of potato (Solanum tuberosum) present every growing season in the Midwestern United States. Most currently grown potato cultivars lack resistance to early blight; therefore, foliar fungicides are relied upon for disease management. Foliar fungicides with high efficacy against the pathogen, such as boscalid, frequently are used under high disease pressure situations, such as potatoes grown under overhead irrigation. Boscalid is a member of the succinate dehydrogenase inhibiting (SDHI) fungicide group and was registered for use on potato in 2005. Baseline sensitivity of A. solani to the SDHI fungicides boscalid, penthiopyrad, and fluopyram using a spore germination assay demonstrated similar intrinsic activity against A. solani with mean EC50 values of 0.33, 0.38, and 0.31 µg/ml, respectively. However, isolates varied in their sensitivity to each of these fungicides, resulting in very low correlations (r) among isolate sensitivity to each fungicide. Resistance to boscalid in A. solani was detected in the states of North Dakota, Minnesota, Nebraska, Texas, Idaho, Wisconsin, and Florida from early blight samples collected in 2010 and 2011. Two phenotypes of boscalid resistance were detected. Approximately 80% of all A. solani assayed were found to have some level of resistance to boscalid with about 5 and 75% of the population moderately resistant (5 to 20 µg/ml) and highly resistant (>20 µg/ml), respectively, to the fungicide. Nearly 99% of all boscalid resistant isolates possessed the F129L mutation in the cytrochrome b gene, indicating that an A. solani population with dual fungicide resistance predominates in the states surveyed. However, A. solani isolates resistant to boscalid remained sensitive to fluopyram, and a large proportion of moderately resistant and resistant isolates were sensitive to penthiopyrad. Disease control data from in vivo trials demonstrated a significant loss of fungicide efficacy when boscalid and fluxapyroxad were used to control moderately and highly resistant isolates of A. solani relative to the control these fungicides provided wild-type isolates. Fluopyram, however, controlled boscalid resistant isolates as well as it controlled wild-type isolates of A. solani. These data will assist potato growers in regions where boscalid resistance is prevalent by assisting them in avoiding fungicides that do not effectively control early blight and in selecting SDHI fungicide molecules that remain efficacious.

Host conservatism, host shifts and diversification across three trophic levels in two Neotropical forests.

Host-parasite systems have been models for understanding the connection between shifts in resource use and diversification. Despite theoretical expectations, ambiguity remains regarding the frequency and importance of host switches as drivers of speciation in herbivorous insects and their parasitoids. We examine phylogenetic patterns with multiple genetic markers across three trophic levels using a diverse lineage of geometrid moths (Eois), specialist braconid parasitoids (Parapanteles) and plants in the genus Piper. Host-parasite associations are mapped onto phylogenies, and levels of cospeciation are assessed. We find nonrandom patterns of host use within both the moth and wasp phylogenies. The moth-plant associations in particular are characterized by small radiations of moths associated with unique host plants in the same geographic area (i.e. closely related moths using the same host plant species). We suggest a model of diversification that emphasizes an interplay of factors including host shifts, vicariance and adaptation to intraspecific variation within hosts.

Generation and large-scale expansion of human inducible regulatory T cells that suppress graft-versus-host disease.

Adoptive transfer of thymus-derived natural regulatory T cells (nTregs) effectively suppresses disease in murine models of autoimmunity and graft-versus-host disease (GVHD). TGFß induces Foxp3 expression and suppressive function in stimulated murine CD4+25- T cells, and these induced Treg (iTregs), like nTreg, suppress auto- and allo-reactivity in vivo. However, while TGFß induces Foxp3 expression in stimulated human T cells, the expanded cells lack suppressor cell function. Here we show that Rapamycin (Rapa) enhances TGFß-dependent Foxp3 expression and induces a potent suppressor function in naive (CD4+ 25-45RA+) T cells. Rapa/TGFß iTregs are anergic, express CD25 at levels higher than expanded nTregs and few cells secrete IL-2, IFNγ or IL-17 even after PMA and Ionomycin stimulation in vitro. Unlike other published methods of inducing Treg function, Rapa/TGFß induces suppressive function even in the presence of memory CD4+ T cells. A single apheresis unit of blood yields an average ~240 × 109 (range ~ 70-560 × 109) iTregs from CD4+25- T cells in ≤ 2 weeks of culture. Most importantly, Rapa/TGFß iTregs suppress disease in a xenogeneic model of GVHD. This study opens the door for iTreg cellular therapy for human diseases.

Functional gametophytic self-incompatibility in a peripheral population of Solanum peruvianum (Solanaceae).

The transition from self-incompatibility to self-compatibility is a common transition in angiosperms often reported in populations at the edge of species range limits. Geographically distinct populations of wild tomato species (Solanum section Lycopersicon (Solanaceae)) have been described as polymorphic for mating system with both self-incompatible and self-compatible populations. Using controlled pollinations and sequencing of the S-RNase mating system gene, we test the compatibility status of a population of S. peruvianum located near its southern range limit. Pollinations among plants of known genotypes revealed strong self-incompatibility; fruit set following compatible pollinations was significantly higher than following incompatible pollinations for all tested individuals. Sequencing of the S-RNase gene in parents and progeny arrays was also as predicted under self-incompatibility. Molecular variation at the S-RNase locus revealed a diverse set of alleles, and heterozygosity in over 500 genotyped individuals. We used controlled crosses to test the specificity of sequences recovered in this study; in all cases, results were consistent with a unique allelic specificity for each tested sequence, including two alleles sharing 92% amino-acid similarity. Site-specific patterns of selection at the S-RNase gene indicate positive selection in regions of the gene associated with allelic specificity determination and purifying selection in previously characterized conserved regions. Further, there is broad convergence between the present and previous studies in specific amino-acid positions inferred to be evolving under positive selection.

Cytomegalovirus-Specific Immunity Recovers More Slowly after Cord Blood Transplantation Compared with Matched Sibling Donor Allogeneic Transplantation.

BACKGROUND: Rapid quantitative recovery of NK cells but slower recovery of T-cell subsets along with frequent viral infections are reported after umbilical cord blood (UCB) compared with matched sibling donor (MSD) hematopoietic cell transplantation (HCT). However, it remains unclear whether increased propensity for viral infections is also a result of slower recovery of virus-specific immunity after UCB as compared to MSD HCT. OBJECTIVES: We examined the differences in the function of virus-specific peripheral blood mononuclear cells (PBMC) after UCB (N=17) vs. MSD (N=9) using previously collected patient blood samples at various time points after HCT. METHODS: Interferon-gamma (IFN-γ) enzyme-linked immune absorbent spot (ELISpot) assay was used to quantify the PBMC frequencies that secrete IFN-γ in response to 11 immunopeptides from 5 common viruses. We included the patients who received the same reduced intensity conditioning regimen without ATG, no systemic glucocorticoids and had no relapse or acute/chronic graft-versus-host disease within 1 year after HCT. RESULTS: The CMV-reactive PBMC frequencies were higher in CMV seropositive vs. seronegative patients after HCT. Among CMV seropositive patients, the frequency of CMV-reactive PBMC was lower after UCB compared to MSD throughout one year of HCT. We observed no differences in virus-specific PBMC responses towards HHV6, EBV, BK, and adenovirus antigens between UCB and MSD. CONCLUSION: Our data demonstrate that the reconstitution of CMV-specific immunity is slower in CMV seropositive recipients of UCB vs. MSD HCT in contrast to other viruses which had similar recoveries. These study findings support implementation of more potent prophylactic strategies for preventing CMV reactivation in CMV seropositive patients receiving UCB HCT.

Electrochemical growth of highly conducting inorganic complexes.

The formation of single crystals of highly conducting inorganic complexes, for example, K(2)Pt(CN)(4)X(0.3) . 3H(2)O (X = Cl, Br), K(1.75)Pt(CN)(4) . 1.5 H(2)O, or K(1.64)Pt(O(2)C(2)O(2)) . 2H(2)O, has been effected via electrochemical growth from concentrated aqueous solutions of potassium tetracyanoplatinate(II) and potassium bis(oxalato)platinate(II).

Dianion Stabilization by (M(C5(CH3)5)2)+: Theoretical Evidence for a Localized Ring in (DDQ)2-.

Organic dianions have been stabilized by (M(C(5)(CH(3))(5))(2))(+), where M is iron or cobalt. This has allowed the structural and spectroscopic characterization of these dianions. The structure of (M(C(5)(CH(3))(5))(2))(2)(+) (DDQ)(2-), where DDQ is 2,3-dichloro-5,6-dicyanobenzoquinone, has been determined by x-ray crystallography. The structure of (DDQ)(2-)is consistent with ab initio molecular orbital calculations that suggest a localizd as opposed to a delocalized (aromatic) ring structure.

Polyploidy and the evolution of gender dimorphism in plants.

Gender dimorphism and polyploidy are important evolutionary transitions that have evolved repeatedly in many plant families. We show that gender dimorphism in North American Lycium (Solanaceae) has evolved in polyploid, self-compatible taxa whose closest relatives are cosexual, self-incompatible diploids. This has occurred independently in South African Lycium. We present additional evidence for this pathway to gender dimorphism from 12 genera involving at least 20 independent evolutionary events. We propose that polyploidy is a trigger of unrecognized importance for the evolution of gender dimorphism, which operates by disrupting self-incompatibility and leading to inbreeding depression. Subsequently, male sterile mutants invade and increase because they are unable to inbreed.

Molecular/Organic ferromagnets.

Quantitative bulk ferromagnetic behavior has been established for the molecular/organic solid [Fe(III)(C(5)Me(5))(2)].(+)[TCNE].(-). Above 16 K the dominant magnetic interactions are along a 1-D chain and, near T(c), 3-D bulk effects as evidenced by the value of the critical exponents dominate the susceptibility. The extended McConnell model was developed and provides the synthetic chemist with guidance for making new molecular materials to study cooperative magnetic coupling in systems. Assuming the electron-transfer excitation arises from the POMO, ferromagnetic coupling by the McConnell mechanism requires stable radicals (neutral, cations/anions, or ions with small diamagnetic counterions) with a non-half-filled POMO. The lowest excited state formed via virtual charge transfer (retro or forward) must also have the same spin multiplicity and mix with the ground state. These requirements limit the structure of a radical to D(2d) or C>/=(3) symmetry where symmetry breaking distortions do not occur. Intrinsic doubly and triply degenerate orbitals are not necessary and accidental degeneracies suffice. To achieve bulk ferromagnetism, ferromagnetic coupling must be established throughout the solid and a microscopic model has been discussed. These requirements are met by [Fe(III)(C(5)Me(5))(2)].(+)[TCNE].(-). Additionally this model suggests that the Ni(III) and Cr(III) analogs should be antiferromagnetic and ferrimagnetic, respectively, as preliminary data suggest. Additional studies are necessary to test and further develop the consequences of these concepts. Some molecular/organic solids comprised of linear chains of alternating metallocenium donors (D) and cyanocarbon acceptors (A) with spin state S = 1/2 (...D.(+)A.(-)D.(+)A.(-)...) exhibit cooperative magnetic phenomena, that is, ferro-, antiferro-, ferri-, and metamagnetism. For [Fe(III)(C(5)Me(5))(2)].(+)[TCNE](-). (Me = methyl; TCNE = tetracyanoethylene), bulk ferromagnetic behavior is observed below the Curie temperature of 4.8 K. A model of configuration mixing of the lowest charge-transfer excited state with the ground state was developed to understand the magnetic coupling as a function of electron configuration and direction of charge transfer. This model predicts that ferromagnetic coupling requires stable radicals with a non-half-filled degenerate valence orbital and a charge-transfer excited state with the same spin multiplicity that mixes with the ground state. Ferromagnetic coupling must dominate in all directions to achieve a bulk ferromagnet. Thus, the primary, secondary, and tertiary structures are crucial considerations for the design of molecular/organic ferromagnets.

Crystal Structure of Hexaazaoctadecahydrocoronene Dication [HAOC]2+, a Singlet Benzene Dication.

The structures of hexaazaoctadecahydrocoronene, [HAOC](n) (n = O, + 2), have been determined by single-crystal x-ray diffraction. Although HAOC is aromatic, its dication has a localized structure that is based upon Jahn-Teller-distorted cyanine/p-phenylenediammonium fragments. The structure is consistent with the singlet ground state as determined by magnetic susceptibility and contrasts with the simplest Hückel expectation of a triplet ground state.

A room-temperature molecular/organic-based magnet.

The reaction of bis(benzene)vanadium with tetracyanoethylene, TCNE, affords an insoluble amorphous black solid that exhibits field-dependent magnetization and hysteresis at room temperature. The critical temperature could not be estimated as it exceeds 350 kelvin, the thermal decomposition temperature of the sample. The empirical composition of the reported material is V(TCNE)x.Y(CH(2)Cl(2)) with x approximately 2 and Y approximately 1/2. On the basis of the available magnetic and infrared data, threedimensional antiferromagnetic exchange of the donor and acceptor spins resulting in ferrimagnetic behavior appears to be the mode of magnetic coupling.

Cloning and characterization of a second complementary DNA for human tryptase.

A second cDNA for human tryptase, called beta-tryptase, was cloned from a mast cell cDNA library in lambda ZAP. Its nucleotide sequence and corresponding amino acid sequence were determined and compared with those of a previously cloned tryptase cDNA, now called alpha-tryptase. The 1,142-base sequence of beta-tryptase encodes a 30-amino acid leader sequence of 3,089 D and a 245-amino acid catalytic region of 27,458 D. The amino acid sequence of beta-tryptase is 90% identical with that of alpha-tryptase, the first 20 amino acids of the catalytic portions being 100% identical. This identity, together with recognition of each recombinant protein by monoclonal antibodies directed against purified tryptase validate the tryptase identity of both alpha-tryptase and beta-tryptase cDNA molecules. Modest differences between the nucleic acid sequences of alpha- and beta-tryptase occurred throughout the cDNA molecules except in the 3' noncoding regions, which were identical. Although most highly conserved regions of amino acid sequence in the trypsin superfamily are conserved in both tryptase molecules, beta-tryptase has one carbohydrate binding site compared to two in alpha-tryptase, and one additional amino acid in the catalytic sequence. Regions of the substrate binding pocket in beta-tryptase (DSCQ, residues 218-221; SWG, residues 243-245) differ slightly from those in alpha-tryptase (DSCK, residues 217-220; SWD, residues 242-244). The presence of both alpha- and beta-tryptase sequences in each haploid genome was indicated by finding alpha- and beta-tryptase specific fragments after amplification by PCR of genomic DNA in 10 unrelated individuals. Localization of both alpha- and beta-tryptase sequences to human chromosome 16 was then performed by analysis of DNA preparations from 25 human/hamster somatic hybrids by PCR. It is now possible to assess the expression of each tryptase cDNA by mast cells and the relationship of each gene product to the active enzyme.

Cloning and characterization of complementary DNA for human tryptase.

The amino acid sequence of human mast cell tryptase was determined from corresponding cDNA cloned from a lambda ZAP library made with mRNA derived from a human mast cell preparation. Tryptase is the major neutral protease present in human mast cells and serves as a specific marker of mast cells by immunohistologic techniques and as a specific indicator of mast cell activation when detected in biologic fluids. Based on nucleic acid sequence, human tryptase consists of a 244-amino acid catalytic portion of 27,423 D with two putative N-linked carbohydrate binding sites and a 30-amino acid leader sequence of 3,048 D. A His74, Asp120, Ser223 catalytic triad and four cystine groups were identified by analogy to other serine proteases. Regions of amino acid sequence that are highly conserved in serine proteases, in general, were conserved in tryptase. The catalytic portion of human tryptase had an 84% amino acid sequence similarity with that of dog tryptase; their leader sequences had a 67% similarity. Asp217 in the substrate binding pocket of human tryptase is consistent with a specificity for Arg and Lys residues at the site of cleavage (P1), whereas Glu245 is consistent with the known preference of human tryptase for substrates with Arg or Lys also at P3, analogous residues also being present in dog tryptase. Asp244, which is substituted for the Gly found in dog tryptase and in most serine proteases, is present in the putative substrate binding pocket and may confer additional substrate specificity on human tryptase for basic residues. Further studies now can be designed to elucidate these structure-function relationships.

Human mast cell proteases and mast cell heterogeneity.

Mast cell neutral proteases are distinctive markers of the MC(T) and MC(TC) cells in humans. Measurements of tryptase levels in vivo serve as an overall indicator of mast cell activity. Further research is needed to evaluate the functional role of these proteases as well as each mast cell type in situations related to both health and disease.