Understanding risks and consequences of pathogen infections on the physiological performance of outmigrating Chinook salmon

The greatest concentration of at-risk anadromous salmonids is found in California (USA)-the populations that have been negatively impacted by the degradation of freshwater ecosystems. While climate-driven environmental changes threaten salmonids directly, they also change the life cycle dynamics and geographic distribution of pathogens, their resulting host-pathogen interactions and potential for disease progression. Recent studies have established the correlation between pathogen detection and salmonid smolt mortality during their migration to the ocean. The objective of the present study was to screen for up to 47 pathogens in juvenile Chinook salmon (Oncorhynchus tshawytscha) that were held in cages at two key sites of the Sacramento River (CA, USA) and measure potential consequences on fish health. To do so, we used a combination of transcriptomic analysis, enzymatic assays for energy metabolism and hypoxia and thermal tolerance measures. Results revealed that fish were infected by two myxozoan parasites: Ceratonova shasta and Parvicapsula minibicornis within a 2-week deployment. Compared to the control fish maintained in our rearing facility, infected fish displayed reduced body mass, depleted hepatic glycogen stores and differential regulation of genes involved in the immune and general stress responses. This suggests that infected fish would have lower chances of migration success. In contrast, hypoxia and upper thermal tolerances were not affected by infection, suggesting that infection did not impair their capacity to cope with acute abiotic stressors tested in this study. An evaluation of long-term consequences of the observed reduced body mass and hepatic glycogen depletion is needed to establish a causal relationship between salmon parasitic infection and their migration success. This study highlights that to assess the potential sublethal effects of a stressor, or to determine a suitable management action for fish, studies need to consider a combination of endpoints from the molecular to the organismal level.

Core Entrustable Professional Activities in Clinical Pharmacology for Entering Residency: Common Problem Drugs and How to Prescribe Them

Although the medical profession strives for safe prescribing, most medications are unique challenges even when prescribed by an experienced provider. In this article we discuss the pitfalls associated with drug interactions between commonly used antibiotics and anticoagulants, the complexities associated with the administration of novel reversible anticoagulants, the often-overlooked severe adverse drug reactions from commonly used classes of medications such as corticosteroids, the nuances of managing an acetaminophen overdose, and uncommon yet serious adverse events associated with the use of contraceptive hormone drugs.

Floating plastics in Adriatic waters (Mediterranean Sea): From the macro- to the micro-scale

Macro- and microplastics abundances were determined in the Adriatic Sea following the MSFD TG10 protocol. The studied areas included populated gulfs, river outlets and offshore waters in five Adriatic countries. The use of small ships enabled us to detect small sized plastics (2.5-5 cm) and record average macroplastics densities of 251 ± 601 items km^-2, one order of magnitude higher than previously considered. Results from manta net tows for microplastics revealed an average abundance of 315,009 ± 568,578 items km^-2 (217 ± 575 g km^-2). We found significantly higher microplastics abundances in nearshore (≤4 km) than in offshore waters (>4 km) and this trend seems to affect also the small sized macro plastic fragments (2.5-5 cm). The dominant polymers were polyethylene and polypropylene while the presence of some rare polymers and waxes used in food and dentistry indicated waste water treatment plants as potential sources of microplastics.

Dosage Adjustments Related to Young or Old Age and Organ Impairment

Differences in physiology related to young or old age and/or organ system impairment alter the absorption, distribution, metabolism, and excretion of many medications and consequently their effectiveness and toxicity. This module discusses common alterations in medication use and dosage that are required in the pediatric age group, in the elderly, and in patients with renal or hepatic disease.

Circulating Type-1 Anti-Tumor CD4(+) T Cells are Preferentially Pro-Apoptotic in Cancer Patients

Cancer patients frequently exhibit a deficiency in Type-1 (but not Type-2 or regulatory) CD4⁺ T cell responses against tumor-associated antigens (TAA), which may limit protection against disease progression or responsiveness to immunotherapy in these individuals. Since such deficiency was acutely evident in patients with active disease (AD), where chronic stimulation of anti-tumor CD4⁺ T cells would be expected and activation-induced cell death may be prevalent, we employed MHC Class II-peptide tetramers to characterize the frequency and apoptotic status of TAA- vs. influenza (FluM1) virus-specific CD4⁺ T cells in the peripheral blood of HLA-DR*0401⁺ patients with melanoma or renal cell carcinoma. We observed that Flu-specific CD4⁺ T cells ranged from 0.17 to 3.89%, while up to approximately 1% of CD4⁺ T cells reacted against individual TAA epitopes derived from the EphA2 or MAGE-6 proteins. The frequencies of EphA2 and MAGE-6-specific CD4⁺ T cells in patients were significantly correlated with AD and gender of the patient (i.e., females > males), while frequencies of Flu-specific CD4⁺ T cells were distributed within a normal range in all patients. Notably, patient CD4⁺ T cells reactive with MHC class II-TAA (but not MHC class II-Flu) tetramers were significantly enriched for a pro-apoptotic (Annexin-V⁺) phenotype, particularly amongst the Th1 (T-bet⁺) subset. These results suggest that the preferential sensitivity of TAA (but not viral)-specific CD4⁺ Th1 cells to apoptosis in melanoma patients with AD will need to be overcome for optimal clinical benefit of immunotherapeutic approaches to be realized.

Heat shock protein 90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin enhances EphA2+ tumor cell recognition by specific CD8+ T cells

EphA2, a member of the receptor tyrosine kinase family, is commonly expressed by a broad range of cancer types, where its level of (over)expression correlates with poor clinical outcome. Because tumor cell expressed EphA2 is a nonmutated "self" protein, specific CD8(+) T cells are subject to self-tolerance mechanisms and typically exhibit only moderate-to-low functional avidity, rendering them marginally competent to recognize EphA2(+) tumor cells in vitro or in vivo. We have recently reported that the ability of specific CD8(+) T cells to recognize EphA2(+) tumor cells can be augmented after the cancer cells are pretreated with EphA2 agonists that promote proteasomal degradation and up-regulated expression of EphA2/class I complexes on the tumor cell membrane. In the current study, we show that treatment of EphA2(+) tumor cells with the irreversible heat shock protein 90 inhibitor, 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), similarly enhances their recognition by EphA2-specific CD8(+) T-cell lines and clones in vitro via a mechanism that is dependent on proteasome and transporter-associated protein function as well as the retrotranslocation of EphA2 into the tumor cytoplasm. When 17-DMAG and agonist anti-EphA2 monoclonal antibodies are coapplied, T-cell recognition of tumor cells is further increased over that observed for either agent alone. These studies suggest that EphA2 represents a novel heat shock protein 90 client protein and that the treatment of cancer patients with 17-DMAG-based "pulse" therapy may improve the antitumor efficacy of CD8(+) T effector cells reactive against EphA2-derived epitopes.

HSP90 inhibitor 17-DMAG enhances EphA2+ tumor cell recognition by specific CD8+ T cells (40.27)

EphA2, a member of receptor tyrosine kinases (RTK), is commonly expressed by a broad range of cancer types, where its level of (over)expression correlates with poor clinical outcome. Since tumor cell expressed EphA2 is a non-mutated "self" protein, specific CD8+ T cells are subject to self-tolerance mechanisms and typically exhibit only moderate-to-low functional avidity, rendering them marginally competent to recognize EphA2+ tumor cells in vitro or in vivo. We have recently reported that the ability of specific CD8+ T cells to recognize EphA2+ tumor cells can be augmented after the cancer cells are pretreated with EphA2 agonists that promote proteasomal degradation (Wesa et al., J. Immunol., in press, 2008). In the current study we show that treatment of EphA2+ tumor cells with the HSP90 inhibitor, 17-DMAG, similarly enhances EphA2 degradation by the proteasome, minimally impairs MHC class I antigen presentign machinery, and increases tumor cell recognition by specific CD8+ T cell lines and clones in vitro. These studies suggest that EphA2 represents a novel HSP90 client protein and that the treatment of cancer patients with 17-DMAG-based "pulse" therapy may improve the anti-tumor efficacy of CD8+ T effector cells reactive against EphA2-derived epitopes.

Enhancement in specific CD8+ T cell recognition of EphA2+ tumors in vitro and in vivo after treatment with ligand agonists

The EphA2 receptor tyrosine kinase is an attractive therapeutic target that is commonly overexpressed on solid tumors, with the degree of overexpression associated with disease progression, metastatic potential, and poor prognosis. Agonistic mAbs or ligand (ephrinA1)-Fc fusion protein are capable of inducing EphA2 internalization and degradation, thereby (at least transiently) eliminating the influence of this oncoprotein. We and others have also shown that EphA2 contains multiple peptide epitopes that can be recognized by effector CD4(+) and CD8(+) T cells isolated from tumor-bearing patients. Herein, we show that "agonist" reagents that trigger the proteasome-dependent degradation of tumor cell EphA2 result in the improved presentation of peptides derived from (both the extracellular and intracellular domains of) EphA2 in MHC class I complexes expressed on the tumor cell membrane for at least 48 h, as manifested by increased recognition by EphA2-specific CD8(+) T cells in vitro. We also observed that while delivery of ephrinA1-Fc fusion protein or agonist mAb into EphA2(+) tumor lesions promotes EphA2 degradation in situ, this single administration of agent does not dramatically alter tumor progression in a humanized SCID model. However, when combined with the adoptive transfer of normally nontherapeutic (human) anti-EphA2 CD8(+) CTL, this dual-agent regimen results in complete tumor eradication. These results suggest that strategies targeting the conditional proteasome-mediated destruction of tumor cell EphA2 may enable EphA2-specific CD8(+) T cells (of modest functional avidity) to realize improved therapeutic potential.

Focus on FOCIS: interleukin 2 treatment associated autoimmunity

A patient from the University of Pittsburgh is presented who developed autoimmunity during IL-2 based combination therapy. IL-2 was originally described as a "T cell growth factor" capable of expanding previously activated T cells, enhancing the cytotoxicity of antigen-specific cytotoxic T cells and NK cells. High dose Interleukin 2 (HDIL2) is now FDA-approved for therapy of patients with metastatic melanoma and renal cell carcinoma, based on its ability to induce durable responses in 5-10% of patients. The antitumor effect of HDIL2 is incompletely understood, but it appears that this regimen alters the balance of immigrant T effector cells in relation to T suppressor cells. It promotes a less immunosuppressive tumor microenvironment, inducing tumor regression in a subset of patients that is yet to be defined. The antitumor activity of IL-2, as for other agents that promote durable antitumor activity against melanoma such as interferon alpha and anti-CTLA4 antibody, is frequently associated with development of autoimmunity as observed in this patient. We present studies investigating the mechanisms for the therapeutic benefit of HDIL2 in melanoma.

A mycoplasma peptide elicits heteroclitic CD4+ T cell responses against tumor antigen MAGE-A6

PURPOSE

Although T-helper (Th) epitopes have been previously reported for many tumor antigens, including MAGE-A6, the relevant HLA-DR alleles that present these peptides are expressed by only a minority of patients. The identification of tumor antigenic epitopes presented promiscuously by many HLA-DR alleles would extend the clinical utility of these peptides in vaccines and for the immunomonitoring of cancer patients.

EXPERIMENTAL DESIGN

A neural network algorithm and in vitro sensitization assays were employed to screen candidate peptides for their immunogenicity.

RESULTS

The MAGE-A6(140-170), MAGE-A6(172-187), and MAGE-A6(280-302) epitopes were recognized by CD4+ T cells isolated from the majority of normal donors and melanoma patients evaluated. Peptide-specific CD4+ T cells also recognized autologous antigen-presenting cell pulsed with recombinant MAGE-A6 (rMAGE) protein, supporting the natural processing and MHC presentation of these epitopes. Given the strong primary in vitro sensitization of normal donor CD4+ T cells by the MAGEA6(172-187) epitope, suggestive of potential cross-reactivity against an environmental stimulus, we identified a highly homologous peptide within the Mycoplasma penetrans HF-2 permease (MPHF2) protein. MPHF2 peptide-primed CD4+ T cells cross-reacted against autologous APC pulsed with the MAGE-A6(172-187) peptide or rMAGE protein and recognized HLA-matched MAGE-A6+ melanoma cell lines. These responses seemed heteroclitic in nature because the functional avidity of MPHF2 peptide-primed CD4+ T cells for the MAGE-A6(172-187) peptide was approximately 1,000 times greater than that of CD4+ T cells primed with the corresponding MAGE-A6 peptide.

CONCLUSIONS

We believe that these novel "promiscuous" MAGE-A6/MPHF2 Th epitopes may prove clinically useful in the treatment and/or monitoring of a high proportion of cancer patients.

Inhibition of cytokine production and cytotoxic activity of human antimelanoma specific CD8+ and CD4+ T lymphocytes by adenosine-protein kinase A type I signaling

The goal of this study was to investigate the effects of adenosine and its stable analogue 2-chloroadenosine (CADO) on the cytotoxic activity and cytokine production by human antimelanoma specific CD8+ and CD4+ T-helper type 1 (Th1) clones. The cytotoxic activity of CD8+ T cells was inhibited by adenosine and CADO. Using Lab MAP multiplex technology, we found that adenosine inhibits production of various cytokines and chemokines by CD8+ and CD4+ T cells. Studies with CGS21680, a specific agonist of adenosine A2A receptor (AdoRA2A), and ZM241385, an AdoRA2-selective antagonist, indicate that the inhibitory effects of adenosine are mediated via cyclic AMP (cAMP)-elevating AdoRA2A, leading to protein kinase A (PKA) activation. Using cAMP analogues with different affinities for the A and B sites of the regulatory subunits of PKAI and PKAII, we found that activation of PKAI, but not of PKAII, mimicked the inhibitory effects of adenosine on T-cell cytotoxic activity and cytokine production. Inhibitors of the PKA catalytic subunits (H89 and PKA inhibitor peptide 14-22) failed to abrogate the inhibitory effects of CADO. In contrast, Rp-8-Br-cAMPS that antagonizes binding of cAMP to the regulatory I subunit and PKA activation was efficient in blocking the inhibitory effect of adenosine on the functional activity of T cells. Our findings on the ability of adenosine to inhibit the effector function of antimelanoma specific T cells suggest that intratumor-produced adenosine could impair the function of tumor-infiltrating T lymphocytes. Thus, blocking the inhibitory activity of tumor-produced adenosine might represent a new strategy for improvement of cancer immunotherapy.

Conditional triggering of EphA2 epitope presentation results in the enhanced tumor cell recognition by specific CTL. (48.25)

The receptor tyrosine kinase EphA2 is over-expressed in numerous carcinomas in association with poor clinical prognosis. While pharmacologic agents that antagonize EphA2-mediated signaling could be contemplated as a therapy, a more preferred result would be to decrease tumor cell EphA2 expression while coordinately enhancing specific immune reactivity to tumor cells. We show that specific mAb triggers the internalization of EphA2, resulting in increased processing of EphA2 protein and presentation of EphA2-derived epitopes in tumor cell HLA class I complexes to CD8+ T cells (detected by IFN-γ production and CD107b translocation). Ab-enhanced CTL recognition is blocked by tumor cell co-treatment with Pseudomonas Exotoxin-A and proteasome inhibitors, but not by chloroquine, suggesting that internalized EphA2 complexes are rapidly translocated into the cytoplasm for delivery of peptides into the class I biosynthetic route. When combined with vaccines designed to augment the frequency of circulating anti-EphA2 CD8+ T cells, this agonist strategy may define an effective therapy for patients harboring EphA2+ cancers.

RTK-based vaccines elicit specific CD8+ T cell responses in HLA-A2 transgenic mice (48.1)

Many receptor tyrosine kinases (RTK) are overexpressed/dysregulated in advanced cancers, serving as negative prognostic indicators. We evaluated the immunogenicity of dendritic cell (DC)/RTK(EphA2, EGFR, Her2/neu)-based vaccines in HLA-A2 (HHD) Tg mice. To enhance the stimulatory capacity of BM-derived DCs, these cells were infected with a recombinant adenovirus encoding mIL-12p70 (Ad.IL12), prior to being pulsed with RTK-derived peptides. We also evaluated a cohort of DC co-infected with both Ad.IL12 and Ad.EphA2. Each of these DC preparations (vs. control DCs) were injected three times s.c. into HHD mice on a weekly schedule. DTH reactions were monitored 48–72h after each vaccination and splenocytes were harvested on d28 and d60 to assess specific CD8+ T cell reactivity (IFN-γ ELISA). Autoimmunity pathology in RTK+ normal tissues (i.e. kidney, liver, lung) were also evaluated for immune infiltration and tissue destruction by (immuno)histochemistry. Vaccines induced specific DTH responses and Tc1 responses in HHD mice, in association with an increased accumulation of CD8+ T cells around proximal endothelial cells (PEC) in the kidney and in the interstitial lung at d28, in the absence of tissue pathology. DC/RTK-based vaccines may promote specific Type-1 immunity that has the potential to eradicate RTK+ tumors, while sparing normal RTK+ tissues.

This work was supported by NIH R01 grant CA114071 (W.J.S.)

SAGE and antibody array analysis of melanoma-infiltrated lymph nodes: identification of Ubc9 as an important molecule in advanced-stage melanomas

Although patients diagnosed with melanoma of </= 1.00 mm thickness have a relatively good cure rate, the prognosis for patients with locally advanced and metastatic melanoma is grave. The discovery of new and effective therapies for this disease depends in large part on molecular studies that will resolve why advanced-stage melanoma is refractory to conventional chemotherapy and radiation therapy. To identify genes that have important functions in advanced-stage melanomas, in particular, in melanoma-infiltrated lymph nodes, which are not well characterized at the molecular level, we generated a LongSAGE library from a melanoma-positive lymph node, and subjected melanoma-infiltrated lymph nodes to protein expression profiling. The data document that the molecular signature of melanoma, which has spread to regional lymph nodes, is very similar to the molecular signature of primary melanomas. Equally important, we provide evidence that the ubiquitin-conjugating enzyme, Ubc9, is expressed at high levels in melanoma-positive lymph nodes, and that it plays a crucial role in preventing advanced-stage melanomas from undergoing chemotherapy-induced apoptosis.

One NY-ESO-1-derived epitope that promiscuously binds to multiple HLA-DR and HLA-DP4 molecules and stimulates autologous CD4+ T cells from patients with NY-ESO-1-expressing melanoma

NY-ESO-1 is expressed by a broad range of human tumors and is often recognized by Abs in the sera of cancer patients with NY-ESO-1-expressing tumors. The NY-ESO-1 gene also encodes several MHC class I- and class II-restricted tumor epitopes recognized by T lymphocytes. In this study we report one novel pan-MHC class II-restricted peptide sequence, NY-ESO-1 87-111, that is capable of binding to multiple HLA-DR and HLA-DP4 molecules, including HLA-DRB1*0101, 0401, 0701, and 1101 and HLA-DPB1*0401 and 0402 molecules. We also demonstrate that peptide NY-ESO-1 87-111 stimulates Th1-type and Th-2/Th0-type CD4(+) T cells and clones when presented in the context of these HLA-DR and HLA-DP4 molecules. Both bulk CD4(+) T cells and CD4(+) T cell clones were capable of recognizing not only peptide-pulsed APCs, but also autologous dendritic cells, either loaded with the NY-ESO-1 protein or transfected with NY-ESO-1 cDNAs. Using IFN-gamma and IL-5 ELISPOT assays and PBL from patients with NY-ESO-1-expressing tumors, we observed the existence of Th1-type circulating CD4(+) T cells recognizing peptide NY-ESO-1 87-111 in the context of HLA-DP4 molecules. Taken together, these data represent the first report of an HLA-DR- and HLA-DP-restricted epitope from a tumor Ag. They also support the relevance of cancer vaccine trials with peptides NY-ESO-1 87-111 in the large number of cancer patients with NY-ESO-1-expressing tumors.

The alternative open reading frame of LAGE-1 gives rise to multiple promiscuous HLA-DR-restricted epitopes recognized by T-helper 1-type tumor-reactive CD4+ T cells

The NY-ESO-1 and LAGE-1 genes are expressed by many human cancers, but not by normal tissues, with the exception of testis and placenta. The NY-ESO-1 and LAGE-1 genes give rise to multiple MHC class I and class II-presented epitopes derived from the open reading frames (ORF) 1 and 2. Here, we have investigated whether NY-ESO-1/LAGE-1 ORF2 encodes promiscuous MHC class II-restricted epitopes. Using a set of overlapping peptides from the ORF2 protein sequence and autologous dendritic cells (DCs) from normal donors and melanoma patients, we have identified three HLA-DRB1*0401-restricted peptide sequences from the LAGE-1 ORF2 that are capable of stimulating T-helper 1-type melanoma-reactive CD4+ T cells. From these bulk CD4+ T cells, we have generated CD4+ T-cell clones able to recognize not only peptide-pulsed DCs but also autologous DCs loaded with the LAGE-1 ORF2 protein. We have demonstrated that these peptides not only bind to multiple HLA-DR molecules apart from HLA-DRB1*0401 but also stimulate CD4+ T cells when presented in the context of these HLA-DR molecules. Furthermore, our binding data have delineated two additional sequences capable of broadly binding to multiple HLA-DR molecules. Altogether, these data support the immunogenicity of NY-ESO-1/LAGE-1 ORF2 gene products and clearly demonstrate their capability to stimulate T-helper 1 type CD4+ T cells. Because of the role of these cells in promoting long-lasting antitumor CTL responses, our data provide a rationale for cancer vaccine trials with peptides derived from the NY-ESO-1/LAGE-1 ORF2 for a large fraction of patients with NY-ESO-1/LAGE-1(+) tumors.

Selenium content and distribution in rat tissues irradiated with gamma rays

The effects of supplementation with selenous yeast and ionizing radiation on selenium (Se) content and distribution were evaluated in rat tissues (liver, kidney, spleen, heart, muscle, blood, front brain, hind brain, hypothalamus, pituitary, adrenal glands, testes, and hair). This study had 16 Se-supplemented (0.5 micrograms Se/d) and 16 placebo adult male Wistar rats. One half of the animals (eight Se-supplemented and eight placebos) were irradiated with a single dose of 4.2 Gy from a Co-60 source and sacrificed 7 d after irradiation along with nonirradiated animals and analyzed for Se content determination. The data obtained showed that selenous yeast supplementation increased Se levels in rat tissues (highest increases in hypothalamus, 161%; hind brain, 126%; spleen, 110%; and adrenal gland, 105%). Ionizing radiation induced significant changes in Se content and distribution (decrease in liver, blood, hair, femoral muscle, spleen, and hypothalamus; increase in kidney, testes, adrenal glands, and brain of placebo group). Supplementation with selenous yeast reduces changes in Se content and distribution after irradiation. It seems that the animal tissue susceptibility to oxidative damage may be correlated to their ability to retain Se in tissues.

Regulation of malate dehydrogenase activity by glutamate, citrate, alpha-ketoglutarate, and multienzyme interaction

Binding experiments indicate that mitochondrial aspartate aminotransferase can associate with the alpha-ketoglutarate dehydrogenase complex and that mitochondrial malate dehydrogenase can associate with this binary complex to form a ternary complex. Formation of this ternary complex enables low levels of the alpha-ketoglutarate dehydrogenase complex, in the presence of the aminotransferase, to reverse inhibition of malate oxidation by glutamate. Thus, glutamate can react with the aminotransferase in this complex without glutamate inhibiting production of oxalacetate by the malate dehydrogenase in the complex. The conversion of glutamate to alpha-ketoglutarate could also be facilitated because in the trienzyme complex, oxalacetate might be directly transferred from malate dehydrogenase to the aminotransferase. In addition, association of malate dehydrogenase with these other two enzymes enhances malate dehydrogenase activity due to a marked decrease in the Km of malate. The potential ability of the aminotransferase to transfer directly alpha-ketoglutarate to the alpha-ketoglutarate dehydrogenase complex in this multienzyme system plus the ability of succinyl-CoA, a product of this transfer, to inhibit citrate synthase could play a role in preventing alpha-ketoglutarate and citrate from accumulating in high levels. This would maintain the catalytic activity of the multienzyme system because alpha-ketoglutarate and citrate allosterically inhibit malate dehydrogenase and dissociate this enzyme from the multienzyme system. In addition, citrate also competitively inhibits fumarase. Consequently, when the levels of alpha-ketoglutarate and citrate are high and the multienzyme system is not required to convert glutamate to alpha-ketoglutarate, it is inactive. However, control by citrate would be expected to be absent in rapidly dividing tumors which characteristically have low mitochondrial levels of citrate.