Innate immunity: Looking beyond T-cells in radiation and immunotherapy combinations

Radiation therapy is an established and effective anti-cancer treatment modality. Extensive pre-clinical experimentation has demonstrated that the pro-inflammatory properties of irradiation may be synergistic with checkpoint immunotherapy. Radiation induces double-stranded DNA breaks (dsDNA). Sensing of the dsDNA activates the cGAS/STING pathway, producing Type 1 interferons essential to recruiting antigen-presenting cells (APCs). Radiation promotes cytotoxic CD8 T-cell recruitment by releasing tumour-associated antigens captured and cross-presented by surveying antigen-presenting cells. Radiation-induced vascular normalisation may further promote T-cell trafficking and drug delivery. Radiation is also immunosuppressive. Recruitment of regulatory T cells (Tregs) and innate cells such as myeloid-derived suppressive cells (m-MDSCs) all counteract the immunostimulatory properties of radiation. Many innate immune cell types operate at the interface of the adaptive immune response. Innate immune cells, such as m-MDSCs, can exert their immunosuppressive effects by expressing immune checkpoints such as PD-L1, further highlighting the potential of combined radiation and checkpoint immunotherapy. Several early-phase clinical studies investigating the combination of radiation and immunotherapy have been disappointing. A greater appreciation of radiotherapy's impact on the innate immune system is essential to optimise radioimmunotherapy combinations. This review will summarise the impact of radiotherapy on crucial cells of the innate immune system and vital immunosuppressive cytokines.

TSTEM-like CAR-T cells exhibit improved persistence and tumor control compared with conventional CAR-T cells in preclinical models

Patients who receive chimeric antigen receptor (CAR)-T cells that are enriched in memory T cells exhibit better disease control as a result of increased expansion and persistence of the CAR-T cells. Human memory T cells include stem-like CD8⁺ memory T cell progenitors that can become either functional stem-like T (T_STEM) cells or dysfunctional T progenitor exhausted (T_PEX) cells. To that end, we demonstrated that T_STEM cells were less abundant in infused CAR-T cell products in a phase 1 clinical trial testing Lewis Y-CAR-T cells (NCT03851146), and the infused CAR-T cells displayed poor persistence in patients. To address this issue, we developed a production protocol to generate T_STEM-like CAR-T cells enriched for expression of genes in cell replication pathways. Compared with conventional CAR-T cells, T_STEM-like CAR-T cells had enhanced proliferative capacity and increased cytokine secretion after CAR stimulation, including after chronic CAR stimulation in vitro. These responses were dependent on the presence of CD4⁺ T cells during T_STEM-like CAR-T cell production. Adoptive transfer of T_STEM-like CAR-T cells induced better control of established tumors and resistance to tumor rechallenge in preclinical models. These more favorable outcomes were associated with increased persistence of T_STEM-like CAR-T cells and an increased memory T cell pool. Last, T_STEM-like CAR-T cells and anti-programmed cell death protein 1 (PD-1) treatment eradicated established tumors, and this was associated with increased tumor-infiltrating CD8⁺CAR⁺ T cells producing interferon-γ. In conclusion, our CAR-T cell protocol generated T_STEM-like CAR-T cells with enhanced therapeutic efficacy, resulting in increased proliferative capacity and persistence in vivo.

CAR-T Plus Radiotherapy: A Promising Combination for Immunosuppressive Tumors

Radiotherapy (RT) is the standard-of-care treatment for more than half of cancer patients with localized tumors and is also used as palliative care to facilitate symptom relief in metastatic cancers. In addition, RT can alter the immunosuppressive tumor microenvironment (TME) of solid tumors to augment the anti-tumor immune response of immune checkpoint blockade (ICB). The rationale of this combination therapy can also be extended to other forms of immunotherapy, such as chimeric antigen receptor T cell (CAR-T) therapy. Similar to ICB, the efficacy of CAR-T therapy is also significantly impacted by the immunosuppressive TME, leading to compromised T cell function and/or insufficient T cell infiltration. In this review, we will discuss some of the key barriers to the activity of CAR-T cells in the immunosuppressive TME and focus on how RT can be used to eliminate or bypass these barriers. We will present the challenges to achieving success with this therapeutic partnership. Looking forward, we will also provide strategies currently being investigated to ensure the success of this combination strategy in the clinic.

Understanding the Role of T-Cells in the Antimyeloma Effect of Immunomodulatory Drugs

Immunomodulatory drugs (IMiDs) are effective treatments for patients with multiple myeloma. IMiDs have pleotropic effects including targeting the myeloma cells directly, and improving the anti-myeloma immune response. In the absence of myeloma cells, lenalidomide and pomalidomide induce CD4⁺ T cell secretion of IL-2 and indirect activation of Natural Killer (NK) cells. In the context of T cell receptor ligation, IMiDs enhance T cell proliferation, cytokine release and Th1 responses, both in vivo and in vitro. Furthermore, combination treatment of IMiDs and myeloma-targeting monoclonal antibodies eg. daratumumab (anti-CD38) and elotuzumab (anti-SLAMF7), checkpoint inhibitors, or bispecific T cell engagers showed synergistic effects, mainly via enhanced T and NK cell dependent cellular toxicity and T cell proliferation. Conversely, the corticosteroid dexamethasone can impair the immune modulatory effects of IMiDs, indicating that careful choice of myeloma drugs in combination with IMiDs is key for the best anti-myeloma therapeutic efficacy. This review presents an overview of the role for T cells in the overall anti-myeloma effects of immunomodulatory drugs.

Single-Cell Gene Expression, Clonality, and Feature Barcoding of Melanoma Tumor-Infiltrating Lymphocytes

We describe here a protocol to measure gene expression, T cell receptor (TCR) sequence, and protein expression by single T cells extracted from melanoma, using 10× Chromium technology. This method includes freezing and thawing of the melanoma infiltrating lymphocytes, staining of cells with fluorescent and barcode-conjugated antibodies, sorting of T cells, and loading the cells on the 10× Chromium Controller. After sequencing, analysis includes quality control, genetic demultiplexing to resolve genetically different samples, and T cell clonality and clustering analysis. Single cell RNA sequencing paints the complete portrait of individual T cells, including their clonality and phenotype, and it reconstructs a complete picture of the T cell infiltrate in a tumor that is represented as cell clustering similar to a pointillism painting.

PVRIG is a novel NK cell immune checkpoint receptor in acute myeloid leukemia

This study explored the novel immune checkpoint poliovirus receptor- related immunoglobulin domain-containing (PVRIG) in acute myeloid leukemia (AML). We showed that AML patient blasts consistently expressed the PVRIG ligand (poliovirus receptor-related 2, PVRL2). Furthermore, PVRIG blockade significantly enhanced naural killer (NK)-cell killing of PVRL2+, poliovirus receptor (PVR)lo AML cell lines, and significantly increased NK-cell activation and degranulation in the context of patient primary AML blasts. However, in AML patient bone marrow, NK-cell PVRIG expression levels were not increased. In order to understand how PVRIG blockade might potentially be exploited therapeutically, we investigated the biology of PVRIG and revealed that NK-cell activation resulted in reduced PVRIG expression on the cell surface. This occurred whether NK cells were activated by tumor cell recognition, cytokines (interleukin 2 [IL-2] and IL-12) or activating receptor stimulation (CD16 and NKp46). PVRIG was present at higher levels in the cytoplasm than on the cell surface, particularly on CD56bright NK cells, which further increased cytoplasmic PVRIG levels following IL-2 and IL-12 activation. PVRIG was continually transported to the cell surface via the endoplasmic reticulum and Golgi in both unstimulated and activated NK cells. Taken together, our findings suggest that anti-PVRIG blocking antibody functions by binding to surface-bound PVRIG, which undergoes rapid turnover in both unstimulated and activated NK cells. We conclude that the PVRIG-PVRL2 immune checkpoint axis can feasibly be targeted with PVRIG blocking antibody for NK-mediated immunotherapy of PVRL2+ AML.

IL-23 costimulates antigen-specific MAIT cell activation and enables vaccination against bacterial infection

Mucosal-associated invariant T (MAIT) cells are activated in a TCR-dependent manner by antigens derived from the riboflavin synthesis pathway, including 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil (5-OP-RU), bound to MHC-related protein-1 (MR1). However, MAIT cell activation in vivo has not been studied in detail. Here, we have found and characterized additional molecular signals required for optimal activation and expansion of MAIT cells after pulmonary Legionella or Salmonella infection in mice. We show that either bone marrow-derived APCs or non-bone marrow-derived cells can activate MAIT cells in vivo, depending on the pathogen. Optimal MAIT cell activation in vivo requires signaling through the inducible T cell costimulator (ICOS), which is highly expressed on MAIT cells. Subsequent expansion and maintenance of MAIT-17/1-type responses are dependent on IL-23. Vaccination with IL-23 plus 5-OP-RU augments MAIT cell-mediated control of pulmonary Legionella infection. These findings reveal cellular and molecular targets for manipulating MAIT cell function under physiological conditions.

Characterization and Purification of Mouse Mucosal-Associated Invariant T (MAIT) Cells

This unit describes the utility of various mouse models of infection and immunization for studying mucosal-associated invariant T (MAIT) cell immunity: MAIT cells can be isolated from the lungs (or from other tissues/organs) and then identified and characterized by flow cytometry using MR1 tetramers in combination with a range of antibodies. The response kinetics, cytokine profiles, and functional differentiation of lung MAIT cells are studied following infection with the bacterial pathogen Legionella longbeachae or Salmonella enterica Typhimurium or immunization with synthetic MAIT cell antigen plus Toll-like receptor agonist. MAIT cells enriched or expanded during the process can be used for further studies. A step-by-step protocol is provided for MAIT cell sorting and adoptive transfer. Mice can then be challenged and MAIT cells tracked and further examined. © 2019 by John Wiley & Sons, Inc.

Mucosal-Associated Invariant T Cells Augment Immunopathology and Gastritis in Chronic Helicobacter pylori Infection

Mucosal-associated invariant T (MAIT) cells produce inflammatory cytokines and cytotoxic granzymes in response to by-products of microbial riboflavin synthesis. Although MAIT cells are protective against some pathogens, we reasoned that they might contribute to pathology in chronic bacterial infection. We observed MAIT cells in proximity to Helicobacter pylori bacteria in human gastric tissue, and so, using MR1-tetramers, we examined whether MAIT cells contribute to chronic gastritis in a mouse H. pylori SS1 infection model. Following infection, MAIT cells accumulated to high numbers in the gastric mucosa of wild-type C57BL/6 mice, and this was even more pronounced in MAIT TCR transgenic mice or in C57BL/6 mice where MAIT cells were preprimed by Ag exposure or prior infection. Gastric MAIT cells possessed an effector memory Tc1/Tc17 phenotype, and were associated with accelerated gastritis characterized by augmented recruitment of neutrophils, macrophages, dendritic cells, eosinophils, and non-MAIT T cells and by marked gastric atrophy. Similarly treated MR1^-/- mice, which lack MAIT cells, showed significantly less gastric pathology. Thus, we demonstrate the pathogenic potential of MAIT cells in Helicobacter-associated immunopathology, with implications for other chronic bacterial infections.

The value of ultrasonography in the diagnosis of appendicitis

INTRODUCTION

Ultrasonography is a commonly used investigation in the UK for patients with right iliac fossa pain where the diagnosis of appendicitis is unclear. The published sensitivity and specificity of ultrasonography is higher than the results observed by clinicians in every day practice. The aim of this study was to elucidate the real-world value of ultrasonography in the diagnosis of appendicitis, and its impact on negative appendicectomy rates (NAR).

METHODS

A retrospective multicentre audit was conducted at three UK hospitals over a twelve month period in 2012.

RESULTS

573 patients underwent ultrasonography prior to appendicectomy. The appendix was not visualised in 45% of scans. The sensitivity and specificity of ultrasonography for the diagnosis of appendicitis was 51.8% and 81.4%. The mean NAR was 26.7%, or 18.3% after a positive ultrasound scan.

CONCLUSION

In clinical practice at UK centres, ultrasonography commonly does not visualise the appendix, and has a low sensitivity for appendicitis. To reduce the NAR, management options include a return to observation and serial examination, increased use of CT or a commitment to improving the performance of ultrasonography.

Streptomycete endophytes from anti-diabetic medicinal plants of the Western Ghats inhibit alpha-amylase and promote glucose uptake

α-amylase inhibitor retards the liberation of glucose from dietary complex carbohydrates and delays the absorption of glucose. The purpose of the study was to isolate and select α-amylase inhibitor-producing endophytic actinomycetes from the leaves and stems of Leucas ciliata and Rauwolfia densiflora, two of the well-known medicinal plants used in the treatment for diabetes. Sterilized plant samples were inoculated on the actinomycete isolation agar medium containing 50 ppm cycloheximide and incubated for 4-8 weeks at room temperature. The actinomycetes were isolated on agar medium and identified on the basis of 16S rRNA sequences, the isolates exhibiting >99% similarities were submitted to NCBI, and gene accession numbers were obtained. They were inoculated to International Streptomyces Project 1 medium (ISP 1) for fermentation. The extracts obtained were tested for the anti-diabetic potential by the inhibition of alpha-amylase by colorimetric assay and glucose uptake in the porcine hemidiaphragm. Streptomyces longisporoflavus (JX965948) isolated from the stem fragments of L. ciliata exhibited alpha-amylase inhibitory activity (IC50 values = 162.3 ± 1.05 μg ml⁻¹) in comparison with the standard Acarbose™ (IC50 value = 73.1 ± 1.12 μg ml⁻¹). Extract of Streptomyces sp. (JQ926174) from R. densiflora indicated glucose uptake in the porcine hemidiaphragm. Results indicate for the first time the potential of endophytic streptomycete extracts with anti-diabetic activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

Endophytic actinomycetes were isolated from two medicinal species of the Western Ghats, a biodiversity 'hotspot' in southern India and screened for the anti-diabetic potential for inhibition of α-amylase and improved glucose uptake in the porcine hemidiaphragm. Results indicate the inhibition of α-amylase by Streptomyces longisporoflavus extract with IC50 values of 162.3 ± 1.05 μg ml⁻¹ in comparison with the standard inhibitor Acarbose™ with IC50 value 73.1 ± 1.12 μg ml⁻¹. Further, extract from Streptomyces sp. showed increased glucose uptake by hemidiaphragm. The present investigation implicates the potential of endophytic actinomycetes as sources of anti-diabetic agents.

Effect of neonatal exposure on male rats to bisphenol A on the expression of DNA methylation machinery in the postimplantation embryo

Bisphenol A (BPA) is used in the production of polycarbonate plastics and epoxy resins. Our previous studies have demonstrated that neonatal exposure of male rats to BPA causes decrease in sperm count and motility, increase in postimplantation loss (POL), ultimately leading to subfertility during adulthood. Epigenetic mechanisms such as DNA methylation play an important role in embryo development. DNA methyltransferases (Dnmts) are the key players involved in regulating DNA methylation marks. The objective of the present study was to determine the mechanism involved in resorption of embryo as a result of BPA exposure. The results of the present study demonstrate that neonatal exposure of male rats to BPA down regulates the gene expression of Dnmts and related transcription factors in resorbed embryos as compared with the viable embryo. Thereby, suggesting that BPA may have altered the sperm epigenome, which might have affected the embryo development and leading to an increase in the POL.

A phase I/II dose-escalation trial of vitamin D3 and calcium in multiple sclerosis

OBJECTIVE

Low vitamin D status has been associated with multiple sclerosis (MS) prevalence and risk, but the therapeutic potential of vitamin D in established MS has not been explored. Our aim was to assess the tolerability of high-dose oral vitamin D and its impact on biochemical, immunologic, and clinical outcomes in patients with MS prospectively.

METHODS

An open-label randomized prospective controlled 52-week trial matched patients with MS for demographic and disease characteristics, with randomization to treatment or control groups. Treatment patients received escalating vitamin D doses up to 40,000 IU/day over 28 weeks to raise serum 25-hydroxyvitamin D [25(OH)D] rapidly and assess tolerability, followed by 10,000 IU/day (12 weeks), and further downtitrated to 0 IU/day. Calcium (1,200 mg/day) was given throughout the trial. Primary endpoints were mean change in serum calcium at each vitamin D dose and a comparison of serum calcium between groups. Secondary endpoints included 25(OH)D and other biochemical measures, immunologic biomarkers, relapse events, and Expanded Disability Status Scale (EDSS) score.

RESULTS

Forty-nine patients (25 treatment, 24 control) were enrolled [mean age 40.5 years, EDSS 1.34, and 25(OH)D 78 nmol/L]. All calcium-related measures within and between groups were normal. Despite a mean peak 25(OH)D of 413 nmol/L, no significant adverse events occurred. Although there may have been confounding variables in clinical outcomes, treatment group patients appeared to have fewer relapse events and a persistent reduction in T-cell proliferation compared to controls.

CONCLUSIONS

High-dose vitamin D (approximately 10,000 IU/day) in multiple sclerosis is safe, with evidence of immunomodulatory effects.

CLASSIFICATION OF EVIDENCE

This trial provides Class II evidence that high-dose vitamin D use for 52 weeks in patients with multiple sclerosis does not significantly increase serum calcium levels when compared to patients not on high-dose supplementation. The trial, however, lacked statistical precision and the design requirements to adequately assess changes in clinical disease measures (relapses and Expanded Disability Status Scale scores), providing only Class level IV evidence for these outcomes.

Management of psychosis in Parkinson's disease

Psychosis is one of the most disabling complications associated with Parkinson's disease (PD) and occurs in up to 30% of PD patients treated chronically with antiparkinsonian drugs. Visual hallucinations, with or without delirium and paranoid delusions, are the most frequent symptoms. Psychosis complicating PD can be more disabling than the motor symptoms of PD; it frequently poses a serious threat to the patient's ability to maintain independence and is the single greatest risk factor for nursing home placement. Choosing an antipsychotic drug for a PD patient is a common clinical dilemma. The conventional antipsychotic drugs are poorly tolerated in PD because of their predictable and at times profound worsening in parkinsonian motor symptoms. The recent availability of atypical antipsychotic drugs that can control psychotic symptoms without compromising motor function has led to significant advances in therapeutic strategies in the management of PD psychosis in the community. This article reviews data on the use of atypical antipsychotics in patients with PD and the current recommendations on their use in the management of PD psychosis.

Role of glutamine synthetase in nitrogen metabolite repression in Aspergillus nidulans

Glutamine synthetase (GS), EC 6.3.1.2, is a central enzyme in the assimilation of nitrogen and the biosynthesis of glutamine. We have isolated the Aspergillus nidulans glnA gene encoding GS and have shown that glnA encodes a highly expressed but not highly regulated mRNA. Inactivation of glnA results in an absolute glutamine requirement, indicating that GS is responsible for the synthesis of this essential amino acid. Even when supplemented with high levels of glutamine, strains lacking a functional glnA gene have an inhibited morphology, and a wide range of compounds have been shown to interfere with repair of the glutamine auxotrophy. Heterologous expression of the prokaryotic Anabaena glnA gene from the A. nidulans alcA promoter allowed full complementation of the A. nidulans glnADelta mutation. However, the A. nidulans fluG gene, which encodes a protein with similarity to prokaryotic GS, did not replace A. nidulans glnA function when similarly expressed. Our studies with the glnADelta mutant confirm that glutamine, and not GS, is the key effector of nitrogen metabolite repression. Additionally, ammonium and its immediate product glutamate may also act directly to signal nitrogen sufficiency.

Treatment of aneurysmal subarachnoid haemorrhage in elderly patients

Spontaneous subarachnoid haemorrhage (SAH) due to ruptured saccular aneurysm is the fourth most frequent cerebrovascular disorder following atherosclerosis, embolism, and primary intracerebral haemorrhage (1). SAH is a common and often devastating condition, which is a significant cause of world-wide morbidity and mortality (2). The aim of this article is to review the epidemiology, pathophysiology and current management of SAH.

Humoral hypercalcemia of malignancy: severe combined immunodeficient/beige mouse model of adult T-cell lymphoma independent of human T-cell lymphotropic virus type-1 tax expression

The majority of patients with adult T-cell leukemia/lymphoma (ATL) resulting from human T-cell lymphotropic virus type-1 (HTLV-1) infection develop humoral hypercalcemia of malignancy (HHM). We used an animal model using severe combined immunodeficient (SCID)/beige mice to study the pathogenesis of HHM. SCID/beige mice were inoculated intraperitoneally with a human ATL line (RV-ATL) and were euthanized 20 to 32 days after inoculation. SCID/beige mice with engrafted RV-ATL cells developed lymphoma in the mesentery, liver, thymus, lungs, and spleen. The lymphomas stained positively for human CD45RO surface receptor and normal mouse lymphocytes stained negatively confirming the human origin of the tumors. The ATL cells were immunohistochemically positive for parathyroid hormone-related protein (PTHrP). In addition, PTHrP mRNA was highly expressed in lymphomas when compared to MT-2 cells (HTLV-1-positive cell line). Mice with lymphoma developed severe hypercalcemia. Plasma PTHrP concentrations were markedly increased in mice with hypercalcemia, and correlated with the increase in plasma calcium concentrations. Bone densitometry and histomorphometry in lymphoma-bearing mice revealed significant bone loss because of a marked increase in osteoclastic bone resorption. RV-ATL cells contained 1.5 HTLV-1 proviral copies of the tax gene as determined by quantitative real-time polymerase chain reaction (PCR). However, tax expression was not detected by Western blot or reverse transcriptase (RT)-PCR in RV-ATL cells, which suggests that factors other than Tax are modulators of PTHrP gene expression. The SCID/beige mouse model mimics HHM as it occurs in ATL patients, and will be useful to investigate the regulation of PTHrP expression by ATL cells in vivo.

In vitro and in vivo functional analysis of human T cell lymphotropic virus type 1 pX open reading frames I and II

Human T lymphotropic virus type 1 (HTLV-1) is a complex retrovirus containing regulatory and accessory genes encoded in four open reading frames (ORF I-IV) of the pX region. It is not clear what role pX ORFs I and II-encoded proteins have in the pathogenesis of the lymphoproliferative diseases associated with HTLV-1 infection. The conserved ORF I encodes for a hydrophobic 12-kDa protein, p12, (I) that contains four SH3 binding motifs (PXXP) that localizes to cellular endomembranes when overexpressed in cultured cells. Differential splicing of pX ORF II results in the production of two nuclear proteins, p13(II) and p30(II). p13(II) also localizes to mitochondria. p30(II) shares homology with the POU family of transcription factors. We have identified functional roles of pX ORF I and ORF II in establishment and maintenance of infection in a rabbit model. To functionally study p12(I) we have tested a proviral clone with selective ablation of ORF I (ACH.p12(I)) for its ability to infect quiescent peripheral blood mononuclear cells (PBMC). Our data indicate that T cells infected with the wild-type clone of HTLV-1 (ACH) are more efficient than ACH.p12(I) in infecting quiescent PBMC. These findings parallel our animal model data and suggest a role for p12(I) in the activation of quiescent lymphocytes, a prerequisite for effective viral replication in vivo. To test the ability of p30(II) to function as a transcription factor we have constructed p30(II) as a Gal4-fusion protein. When transfected with Gal4-driven luciferase reporter genes, the p30(II)-Gal4-fusion protein induces transcriptional activity up to 50-fold in both 293 and HeLa-Tat cells. These systems will be useful to identify molecular mechanisms that explain the functional role of pX ORF I and ORF II-encoded proteins in HTLV-1 replication.

Comparison of four components of sensory gating in schizophrenia and normal subjects: a preliminary report

Dysfunction of sensory gating has been implicated in the pathophysiology of schizophrenia. The goal of this study was to provide evidence that sensory gating dysfunction in schizophrenia patients is a compounded problem with difficulty in filtering out irrelevant input and filtering in relevant input at both an early-preattentive stage and a later, early-attentive stage of information processing. Four components of sensory gating were examined in 12 medicated, stable schizophrenia patients and 12 age- and sex-matched normal control subjects. Evoked potential paradigms designed to examine the effects of stimulus repetition and stimulus change were utilized. Attenuation of the amplitude of the P50 and the N100 evoked potentials with stimulus repetition was significantly decreased in schizophrenia patients as compared to normal control subjects. The presentation of deviant stimuli caused the degree of attenuation to decrease in normal subjects. This effect was much decreased (and at times reversed) in schizophrenia subjects. These data suggest that schizophrenia patients have difficulty inhibiting incoming, irrelevant stimuli and responding to incoming, significant input as measured by preattentive EPs (P50). The data also suggest that similar abnormalities can be demonstrated at a slightly later phase of information processing (i.e. early-attentive phase) using the N100 EP.

Proliferation response to interleukin-2 and Jak/Stat activation of T cells immortalized by human T-cell lymphotropic virus type 1 is independent of open reading frame I expression

Human T-cell lymphotropic virus type 1 (HTLV-1), a complex retrovirus, encodes a hydrophobic 12-kD protein from pX open reading frame (ORF) I that localizes to cellular endomembranes and contains four minimal SH3 binding motifs (PXXP). We have demonstrated the importance of ORF I expression in the establishment of infection and hypothesize that p12(I) has a role in T-cell activation. In this study, we tested interleukin-2 (IL-2) receptor expression, IL-2-mediated proliferation, and Jak/Stat activation in T-cell lines immortalized with either wild-type or ORF I mutant clones of HTLV-1. All cell lines exhibited typical patterns of T-cell markers and maintained mutation fidelity. No significant differences between cell lines were observed in IL-2 receptor chain (alpha, beta, or gamma(c)) expression, in IL-2-mediated proliferation, or in IL-2-induced phosphorylated forms of Stat3, Stat5, Jak1, or Jak3. The expression of ORF I is more likely to play a role in early HTLV-1 infection, such as in the activation of quiescent T cells in vivo.

CSF monoamine metabolite and beta endorphin levels in recently detoxified alcoholics and healthy controls: prediction of alcohol cue-induced craving?

BACKGROUND

Abnormalities in central neurotransmitter systems have been described in alcohol-dependent individuals and may contribute to alcohol craving. This study compared cerebrospinal fluid (CSF) levels of monoamine metabolites and beta endorphin levels in samples from early-onset alcohol-dependent patients (n = 20), late-onset alcohol-dependent patients (n = 14), and healthy controls (n = 23). It also evaluated whether these CSF measures levels predicted the degree of craving experienced in response to an alcohol cue.

METHODS

Individuals meeting DSM-III and -IV R-criteria for alcohol dependence, 1 to 3 months postdetoxification, and healthy controls underwent a lumbar puncture. Patients also completed a cue exposure test day between 3 and 15 days later.

RESULTS

Alcohol-dependent patients had lower CSF levels of the norepinephrine metabolite MHPG compared with the healthy subjects, but this difference disappeared when differences in age between the groups were accounted for. No other group comparisons between patients and healthy subjects reached significance. CSF levels of the dopamine metabolite HVA were significantly higher in the early-onset patients compared with the late-onset patients and controls. The CSF measures did not predict the precue levels of craving, or the increase in craving after alcohol cue exposure.

CONCLUSIONS

These results are inconclusive about the role of monoaminergic dysregulation in recovering alcoholics. They also question the utility of these CSF measures to predict alcohol cue reactivity in patients who have been sober at least 1 month.

No evidence of altered in vivo benzodiazepine receptor binding in schizophrenia

Deficits in gamma-amino-butyric acid (GABA) neurotransmitter systems have been implicated in the pathophysiology of schizophrenia for more than two decades. Previous postmortem and in vivo studies of benzodiazepine (BDZ) receptor density have reported alterations in several brain regions of schizophrenic patients. The goal of this study was to better characterize possible alterations of the in vivo regional distribution volume (VT) of BDZ receptors in schizoprenia, using the selective BDZ antagonist [123I]iomazenil and single photon emission computerized tomography (SPECT). Regional BDZ VT was measured under sustained radiotracer equilibrium conditions. The reproducibility and reliability of this measurement was established in four healthy volunteers. No differences in regional BDZ VT were observed between 16 male schizophrenic patients and 16 matched controls. No relationships were observed between BDZ VT and severity of psychotic symptoms in any of the regions examined. In conclusion, this study failed to identify alterations of BDZ receptors density in schizoprenia. If this illness is associated with deficits in GABA transmission, these deficits do not substantially involve BDZ receptor expression or regulation.

Evaluation of new vaccines in the mouse and guinea pig model of tuberculosis

The results of this study provide the first evidence that two completely separate vaccine approaches, one based on a subunit vaccine consisting of a mild adjuvant admixed with purified culture filtrate proteins and enhanced by the cytokine interleukin-2 and the second based on immunization with DNA encoding the Ag85A protein secreted by Mycobacterium tuberculosis, could both prevent the onset of caseating disease, which is the hallmark of the guinea pig aerogenic infection model. In both cases, however, the survival of vaccinated guinea pigs was shorter than that conferred by Mycobacterium bovis BCG, with observed mortality of these animals probably due to consolidation of lung tissues by lymphocytic granulomas. An additional characteristic of these approaches was that neither induced skin test reactivity to commercial tuberculin. These data thus provide optimism that development of nonliving vaccines which can generate long-lived immunity approaching that conferred by the BCG vaccine is a feasible goal.

7diffuse melanotic lesion of the iris as a presenting feature of ciliary body melanocytoma: report of a case and review of the literature

Melanocytoma of the ciliary body is quite rare. Although the tumor is benign, it can spread to the surrounding structures, causing glaucoma and giving an erroneous impression of melanoma. We report a case of melanocytoma of the ciliary body in a 19-year-old woman who presented with diffuse melanocytic proliferation of the iris with uncontrolled secondary glaucoma and a subconjunctival pigmented mass. Fine-needle aspiration of the iris lesion and a histopathologic study of the subconjunctival mass could not rule out melanoma. Enucleation of the painful glaucomatous eye showed evidence of ciliary body melanocytoma with extension into the angle structures as well as the subconjunctival tissue.

The course of Mycobacterium tuberculosis infection in the lungs of mice lacking expression of either perforin- or granzyme-mediated cytolytic mechanisms

CD8 T cells have been shown to be protective against Mycobacterium tuberculosis infections in the mouse. These cells have been shown to be cytolytic toward M. tuberculosis-infected cells and have also been shown to release the protective cytokine gamma interferon in response to mycobacterial antigen. It has therefore been unclear how these cells mediate their protective response. To dissect this problem, we compared the courses of M. tuberculosis infections in control, perforin gene-knockout, and granzyme gene-knockout mice exposed by the realistic pulmonary route. The inability to express either of these molecules limits the expression of the major lytic pathway but does not appear to influence the course of the infection or result in any discernible histologic differences. These data seem to rule against a lytic role for CD8 T cells in the lungs and hence tend to suggest instead that another type of mechanism, such as cytokine secretion by these cells, is their primary mode of action.

Immunogenicity and protective efficacy of a tuberculosis DNA vaccine

Tuberculosis is the most widespread and lethal infectious disease affecting humans. Immunization of mice with plasmid DNA constructs encoding one of the secreted components of Mycobacterium tuberculosis, antigen 85 (Ag85), induced substantial humoral and cell-mediated immune responses and conferred significant protection against challenge with live M. tuberculosis and M. bovis bacille Calmette-Guérin (BCG). These results indicate that immunization with DNA encoding a mycobacterial antigen provides an efficient and simple method for generating protective immunity and that this technique may be useful for defining the protective antigens of M. tuberculosis, leading to the development of a more effective vaccine.

Translation of the open reading frame encoded by comS, a gene of the srf operon, is necessary for the development of genetic competence, but not surfactin biosynthesis, in Bacillus subtilis

A small open reading frame, comS of the srf operon, is the site of mutations that impair competence development in Bacillus subtilis. comS open reading frame translation was required for competence, as was confirmed by the suppression of a comS amber mutation [comS(Am)] by the nonsense suppressor sup-3. comS(Am), when introduced into the srf operon, eliminated late competence gene expression but had no significant effect on surfactin production.

Identification of comS, a gene of the srfA operon that regulates the establishment of genetic competence in Bacillus subtilis

Genetic competence (the ability to internalize exogenous DNA) in Bacillus subtilis is dependent on a regulatory pathway that activates the expression of a battery of competence-specific genes. The srfA operon, encoding the subunits of surfactin synthetase, which catalyzes the nonribosomal synthesis of the peptide antibiotic surfactin, also functions in the competence regulatory pathway. The DNA encoding only one of the seven amino acid-activating domains of surfactin synthetase, the valine-activating domain (srfAB1), is necessary for competence. Deletion analysis revealed that a 569-bp fragment of srfAB1, fused to the srfA promoter, complements a srfA deletion mutation (delta srfA) with respect to competence. This fragment contains an open reading frame consisting of 46 amino acids (orf46), which is out of frame with srfAB1. A frameshift mutation in srfAB upstream of orf46 has no effect on competence but a frameshift and nonsense mutation in orf46 resulted in failure to complement the delt srfA mutation. These results indicate that orf46 encodes the srfA-associated competence regulatory factor. Computer-aided analysis of the putative orf46 product (ComS) shows similarity to the homeodomain of the POU domain class of eukaryotic transcriptional regulators.

Analysis of a mutant amino acid-activating domain of surfactin synthetase bearing a serine-to-alanine substitution at the site of carboxylthioester formation

The reactive serine of the TGGHSL thioester binding motif of the first amino acid-activating domain of surfactin synthetase was replaced by alanine using site-directed mutagenesis. The multienzyme from cells of the resulting mutant lost its ability for thioester formation with L-Glu and was therefore inactive in surfactin production. The thiolation reactions catalyzed by the other amino acid-activating domains of surfactin synthetase were not affected by the mutation. The results show that L-Glu is activated at the first domain of surfactin synthetase, and give further evidence that a serine residue is essential for substrate amino acid activation at the reaction centers of peptide synthetases.

Amino-acylation site mutations in amino acid-activating domains of surfactin synthetase: effects on surfactin production and competence development in Bacillus subtilis

The part of the srfA operon of Bacillus subtilis that contains the region required for competence development is composed of the first four amino acid-activating domains which are responsible for the incorporation of Glu, Leu, D-Leu, and Val into the peptide moiety of the lipopeptide surfactin. Ser-to-Ala substitutions were made in the amino-acylation site of each domain, and their effects on surfactin production and competence development were examined. All of the mutations conferred a surfactin-negative phenotype, supporting the finding that the conserved Ser in the amino-acylation site is required for peptide synthesis. However, none of the mutations affected significantly competence development or the expression of a lacZ fusion to the late competence operon comG. This, coupled with recent findings that only the fourth, Val-activating, domain is required for competence, suggests that some activity, other than amino-acylation and perhaps unrelated to peptide synthesis, possessed by the fourth domain is involved in the role of srfA in regulating competence development.

Nucleotide sequence of 5' portion of srfA that contains the region required for competence establishment in Bacillus subtilus

The nucleotide sequence of the 20,535 base pairs of the 5' end of the srfA operon, containing the region required for competence development, was determined. This included the srfA promoter region, the first open reading frame, srfAA, encoding surfactin synthetase I and part of the second open reading frame, srfAB, encoding surfactin synthetase II. Three amino acid-activating domains characteristic of those found in peptide synthetases could be discerned in both srfAA (activating Glu, Leu and D-Leu) and srfAB (activating Val, Asp, and D-Leu). The presence of a conserved spacer motif in the amino-terminal end of srfAA suggests that the srfAA product may not initiate surfactin synthesis. The portion of srfA that contains the region required for competence is composed of srfAA and the first amino acid-activating domain of srfAB.

Biosynthesis of lipid-linked oligosaccharides. I. Preparation of lipid-linked oligosaccharide substrates

In order to purify the glycosyltransferases involved in the assembly of lipid-linked oligosaccharides and to be able to study the acceptor substrate specificity of these enzymes, methods were developed to prepare and purify a variety of lipid-linked oligosaccharides, differing in the structure of the oligosaccharide moiety. Thus, Man9 (GlcNAc)2-pyrophosphoryl-dolichol was prepared by isolation and enzymatic synthesis using porcine pancreatic microsomes, while Glc3Man9(GlcNAc)2-PP-dolichol was isolated from Madin-Darby canine kidney cells. Treatment of these oligosaccharide lipids with a series of selected glycosidases led to the preparation of Man alpha 1,2Man alpha 1,2Man alpha 1,3[Man alpha 1,6(Man alpha 1,3)Man alpha 1,6]Man beta 1,4GlcNAc beta 1,4GlcNAc-PP-dolichol; Man alpha 1,2Man alpha 1,2Man alpha 1,3[Man alpha 1,6]Man beta 1,4GlcNAc beta 1, 4GlcNac-PP-dolichol; and Man alpha 1,6(Man alpha 1,3)Man alpha 1, 6[Man alpha 1,3]Man beta 1,4GlcNAc-beta 1,4GlcNAc-PP-dolichol. The preparation, isolation, and characterization of each of these lipid-linked oligosaccharide substrates are described.

An A to T transversion at position -5 of the factor IX promoter results in hemophilia B

The molecular pathology that results in hemophilia B has been determined by many studies to be highly variable. Several point mutations have been identified in a 40-bp region within the Factor IX promoter. These include mutations at nucleotides -20, -6, +8, and +13. Here we report an A to T transversion at position -5 of the Factor IX gene. There is strong circumstantial evidence to support an important role for this region of the Factor IX promoter in the developmental regulation of the gene through the binding of specific transcription factors.

Application of an N-(4-azido-2,3,5,6-tetrafluorobenzoyl)tyrosine-substituted peptide as a heterobifunctional cross-linking agent in a study of protein O-glycosylation in yeast

In order to investigate the O-mannosyltransferase involved in the initial O-mannosylation of glycoproteins in Saccharomyces cerevisiae, a photoactive hexapeptide, [125I]-N-(4-azido-2,3,5,6-tetrafluorobenzoyl)-3-iodo-Tyr-Asn-Pro-T hr-Ser-Val ([125I]azidoTyr-peptide), was synthesized by solid-phase techniques using a new photoactive cross-linking reagent, N-(4-azido-2,3,5,6-tetrafluorobenzoyl)tyrosine, and resin-bound Asn-Pro-Thr(tBu)-Ser(tBu)-Val. When this modified hexapeptide substrate was incubated with O-mannosyltransferase preparations, the hexapeptide was an acceptor of [14C]-mannose from dolichol phosphate-[14C]mannose. After partially purifying the O-mannosyltransferase and photolabeling these enzyme preparations with [125I]azidoTyr-peptide, a ca. 82-kDa protein was shown to be the only apparent photolabeled protein that was protected by unmodified hexapeptide. This ca. 82-kDa protein may be the catalytic subunit of the O-mannosyltransferase. The susceptibility of the N-(4-azido-2,3,5,6-tetrafluorobenzoyl) moiety to reducing agents in aqueous buffers was also examined.

Ulnar neuropathy at the elbow in diamond assorters

Unilateral ulnar neuropathy at the elbow was detected in 12 men employed as diamond assorters. Asymptomatic diamond assorters were studied as controls. In the symptomatics, the ulnar neuropathy was restricted to the hand which held the eye-glass used for inspecting the diamonds. Electrophysiological studies using several parameters revealed neurapraxia sometimes combined with axonal degeneration in the ulnar nerve at the elbow, compatible with compression at that site. The most sensitive parameters of abnormality in the symptomatic subjects were segmental slowing of motor nerve conduction velocity across the elbow (P less than 0.001) and the amplitude of the compound muscle action potential obtained on stimulating the nerve above the elbow (P less than 0.001). In the 18 asymptomatic diamond assorters, electrophysiological studies revealed an ulnar neuropathy in two (again in the hand used for holding the eye-glass). Ulnar mononeuropathy at the elbow thus seems to be an occupational hazard for diamond assorters and it is worthwhile to elicit occupational history from patients presenting with an ulnar mononeuropathy, especially in Bombay and Gujarat where diamond industry is concentrated.

Partial purification of a mannosyltransferase involved in the O-mannosylation of glycoproteins from Saccharomyces cerevisiae

The mannosyltransferase that catalyses the transfer of mannose from dolichyl-phosphate-mannose (Dol-P-Man) to the hydroxyl group of serine/threonine residues in the acceptor peptide (Tyr-Asn-Pro-Thr-Ser-Val) was partially purified approximately 150-fold from the microsomal membrane fraction of Saccharomyces cerevisiae. The membrane-bound enzyme was solubilized with 0.5% Triton X-100 at a protein:detergent ratio of 2:1, and was then purified by ion-exchange chromatography on DEAE-cellulose, followed by hydroxyapatite column chromatography. The partially purified enzyme had a pH optimum of 7.2 and required Mg2+ at an optimum concentration of 10 mM for activity. The apparent mol. wt of the enzyme, as estimated by gel filtration on Sephacryl S-300, was approximately 125 kDa. The activity of the partially purified enzyme was greatly stimulated by phosphatidylcholine (PC), while other naturally occurring phosphoglycerides had no significant effect. The extent of activation of mannosyltransferase activity was greatly affected by the number of carbons and the degree of saturation/unsaturation of the fatty acid substituents, as well as by their position on the glycerol moiety of the PC molecule. Maximum stimulation of the mannosyltransferase activity was induced by a PC derivative in which both sn-1 and sn-2 positions on the glycerol moiety were occupied by C12:0 fatty acids. In general, mannosyltransferase was found to exhibit greater specificity for the L-alpha-PC derivatives in which the sn-2 position of the glycerol contained a saturated fatty acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary tuberculosis with multiple saccular aneurysms of the aorta--a case report

A forty-eight-year-old man presented with cavitary pulmonary tuberculosis and widening of the mediastinum. Mediastinal widening was due to multiple saccular aneurysms of the ascending aorta and the arch of the aorta. The various presentations of tubercular aortitis and the reasons for considering alternative etiology for the thoracic aneurysms in this case are discussed. The authors report this interesting association of pulmonary tuberculosis with luetic aortic aneurysm.

Herpes zoster in mesothelioma. A case report

Diffuse mesothelioma with a large pleural effusion was diagnosed nine months after the appearance of herpes zoster in the overlying thoracic segment in a patient presenting with chest pain mimicking post-herpetic neuralgia. Clinical implications of such an association are discussed.

Eosinophilic cystitis

A case of eosinophilic cystitis characterized by profuse haematuria and spontaneous recovery is being reported. This is probably the first case report in Indian literature.

Phospholipid transfer protein-mediated incorporation and subcellular distribution of exogenous phosphatidylcholine and sphingomyelin in cultured neuroblastoma cells

Murine neuroblastoma cells (strain N1E-115) were incubated with 2-[fatty acyl-14 C]acylphosphatidylcholine/sphingomyelin or phosphatidylcholine/[choline-3H]sphingomyelin liposomes (1:1, mol/mol; 1.2 mumol total lipid/mg cell protein) in the presence of partially purified rat liver phospholipid transfer protein (2.5 mg/ml), cytochalasin B (50 microM) and 2-deoxyglucose (50 mM) for 10 min. Washed cells were chased for periods of up to 45 min at 37 degrees C with medium containing transfer protein and unlabeled liposomes. Total transfer protein-dependent incorporation of [14C]phosphatidylcholine ([14C] PC) and [3H]sphingomyelin was 136.7 +/- 26.5(n = 5) and 23.7 +/- 5.4(n = 6) nmol/mg protein per 10 min incubation, respectively, (mean +/- S.D.). Incorporation of [14C]PC into the mitochondrial membrane fraction was 128-fold greater (nmol/mg protein) than incorporation of [3H]sphingomyelin. In contrast, incorporation of [3H]sphingomyelin into a fraction enriched in plasma membrane and into microsomes was 1.4- and 2.6-fold greater, respectively, than incorporation of [14C]PC. During the chase periods, the specific activities of total cellular phospholipids decreased as intact [14C]PC and [3H]sphingomyelin accumulated in the culture medium. In the case of cells labeled with [14C]PC, the effect was due primarily to a decrease in the amount of labeled phospholipid in the mitochondrial fraction; in the case of cells labeled with [3H]sphingomyelin, the decrease in activity was greatest in microsomal and plasma membrane phospholipids. The rate and extent of non-endocytotic incorporation of exogenous phosphatidylcholine into the cell membrane of cultured neuroblastoma cells, and its subsequent subcellular disposition, is different from that of exogenous sphingomyelin. Whereas PC is evidently incorporated into and turned over most rapidly in fraction enriched in mitochondrial membranes, sphingomyelin appears to be preferentially incorporated into microsomal and plasma membrane.