Scalp eschar and neck lymphadenopathy after tick bite (SENLAT) caused by Bartonella henselae in Korea: a case report.

BACKGROUND: Tick-borne lymphadenopathy (TIBOLA) is an infectious disease, mainly caused by species from the spotted fever group rickettsiae and is characterized by enlarged lymph nodes following a tick bite. Among cases of TIBOLA, a case of scalp eschar and neck lymphadenopathy after tick bite (SENLAT) is diagnosed when an eschar is present on the scalp, accompanied by peripheral lymphadenopathy (LAP). Only a few cases of SENLAT caused by Bartonella henselae have been reported. CASE PRESENTATION: A 58-year-old male sought medical advice while suffering from high fever and diarrhea. Three weeks before the visit, he had been hunting a water deer, and upon bringing the deer home discovered a tick on his scalp area. Symptoms occurred one week after hunting, and a lump was palpated on the right neck area 6 days after the onset of symptoms. Physical examination upon presentation confirmed an eschar-like lesion on the right scalp area, and cervical palpation revealed that the lymph nodes on the right side were non-painful and enlarged at 2.5 × 1.5 cm. Fine needle aspiration of the enlarged lymph nodes was performed, and results of nested PCR for the Bartonella internal transcribed spacer (ITS) confirmed B. henselae as the causative agent. CONCLUSION: With an isolated case of SENLAT and a confirmation of B. henselae in Korea, it is pertinent to raise awareness to physicians in other Asian countries that B. henselae could be a causative agent for SENLAT.

Human CD141+ dendritic cells generated from adult peripheral blood monocytes.

Human CD141+ dendritic cells (DCs), specialized for cross-presentation, have been extensively studied in the development of DC-based therapy against cancer. A series of attempts was made to generate CD141+ DCs from cord blood CD34+ hematopoietic progenitors to overcome the practical limitation of in vivo rareness. In the present study, we identified a culture system that generates high CD141+ DCs. After culture of CD14+ monocytes in the presence of granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4 for 8 days, CD141 was detected on cells that adhered to the bottom of the culture plate. The attached cells exhibited typical features of immature monocyte-derived DCs (moDCs), except for higher CD86 expression, more dendrites and higher granularity compared with those that did not attach. With 3 additional days of culture, increased CD141 expression on the cells was retained along with adhesion ability and partial expression of CLEC9A, a c-type lectin receptor. Furthermore, the cells exhibited effective uptake of dead cells. Interestingly, the attached moDCs differently responded to polyinosinic:polycytidylic acid (poly I:C) stimulation as well as a mixed lymphocyte reaction. Collectively, our findings show that human CD141+ DCs can be sufficiently generated from peripheral blood CD14+ monocytes, potentiating further investigation into generation of higher yields of cross-priming human DCs in vitro.

Transcription Factor KLF10 Constrains IL-17-Committed Vγ4+ γδ T Cells.

γδ T cells, known to be an important source of innate IL-17 in mice, provide critical contributions to host immune responses. Development and function of γδ T cells are directed by networks of diverse transcription factors (TFs). Here, we examine the role of the zinc finger TFs, Kruppel-like factor 10 (KLF10), in the regulation of IL-17-committed CD27- γδ T (γδ27--17) cells. We found selective augmentation of Vγ4+ γδ27- cells with higher IL-17 production in KLF10-deficient mice. Surprisingly, KLF10-deficient CD127hi Vγ4+ γδ27--17 cells expressed higher levels of CD5 than their wild-type counterparts, with hyper-responsiveness to cytokine, but not T-cell receptor, stimuli. Thymic maturation of Vγ4+ γδ27- cells was enhanced in newborn mice deficient in KLF10. Finally, a mixed bone marrow chimera study indicates that intrinsic KLF10 signaling is requisite to limit Vγ4+ γδ27--17 cells. Collectively, these findings demonstrate that KLF10 regulates thymic development of Vγ4+ γδ27- cells and their peripheral homeostasis at steady state.

Nation-wide surveillance of human acute respiratory virus infections between 2013 and 2015 in Korea.

The prevalence of eight respiratory viruses detected in patients with acute respiratory infections (ARIs) in Korea was investigated through analysis of data recorded by the Korea Influenza and Respiratory Viruses Surveillance System (KINRESS) from 2013 to 2015. Nasal aspirate and throat swabs specimens were collected from 36 915 patients with ARIs, and viral nucleic acids were detected by real-time (reverse-transcription) polymerase chain reaction for eight respiratory viruses, including human respiratory syncytial viruses (HRSVs), influenza viruses (IFVs), human parainfluenza viruses (HPIVs), human coronaviruses (HCoVs), human rhinovirus (HRV), human adenovirus (HAdV), human bocavirus (HBoV), and human metapneumovirus (HMPV). The overall positive rate of patient specimens was 49.4% (18 236/36 915), 5% of which carried two or more viruses simultaneously. HRV (15.6%) was the most predominantly detected virus, followed by IFVs (14.6%), HAdV (7.5%), HPIVs (5.8%), HCoVs (4.2%), HRSVs (3.6%), HBoV (1.9%), and HMPV (1.6%). Most of the ARIs were significantly correlated with clinical symptoms of fever, cough, and runny nose. Although HRV and HAdV were frequently detected throughout the year in patients, other respiratory viruses showed apparent seasonality. HRSVs and IFVs were the major causative agents of acute respiratory diseases in infants and young children. Overall, this study demonstrates a meaningful relationship between viral infection and typical manifestations of known clinical features as well as seasonality, age distribution, and co-infection among respiratory viruses. Therefore, these data could provide useful information for public health management and to enhance patient care for primary clinicians.

Rapamycin-induced autophagy restricts porcine epidemic diarrhea virus infectivity in porcine intestinal epithelial cells.

Porcine epidemic diarrhea virus (PEDV) invades porcine intestinal epithelial cells (IECs) and causes diarrhea and dehydration in pigs. In the present study, we showed a suppression of PEDV infection in porcine jejunum intestinal epithelial cells (IPEC-J2) by an increase in autophagy. Autophagy was activated by rapamycin at a dose that does not affect cell viability and tight junction permeability. The induction of autophagy was examined by LC3I/LC3II conversion. To confirm the autophagic-flux (entire autophagy pathway), autophagolysosomes were examined by an immunofluorescence assay. Pre-treatment with rapamycin significantly restricted not only a 1 h infection but also a longer infection (24 h) with PEDV, while this effect disappeared when autophagy was blocked. Co-localization of PEDV and autophagosomes suggests that PEDV could be a target of autophagy. Moreover, alleviation of PEDV-induced cell death in IPEC-J2 cells pretreated with rapamycin demonstrates a protective effect of rapamycin against PEDV-induced epithelial cell death. Collectively, the present study suggests an early prevention against PEDV infection in IPEC-J2 cells via autophagy that might be an effective strategy for the restriction of PEDV, and opens up the possibility of the use of rapamycin in vivo as an effective prophylactic and prevention treatment.

A Bacterial Metabolite, Compound K, Induces Programmed Necrosis in MCF-7 Cells via GSK3ß.

Ginsenosides, the major active component of ginseng, are traditionally used to treat various diseases, including cancer, inflammation, and obesity. Among these, compound K (CK), an intestinal bacterial metabolite of the ginsenosides Rb1, Rb2, and Rc from Bacteroides JY-6, is reported to inhibit cancer cell growth by inducing cell-cycle arrest or cell death, including apoptosis and necrosis. However, the precise effect of CK on breast cancer cells remains unclear. MCF-7 cells were treated with CK (0-70 micrometer) for 24 or 48 h. Cell proliferation and death were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays, respectively. Changes in downstream signaling molecules involved in cell death, including glycogen synthase kinase 3ß (GSK3ß), GSK3ß, ß-catenin, and cyclin D1, were analyzed by western blot assay. To block GSK3ß signaling, MCF-7 cells were pretreated with GSK3ß inhibitors 1 h prior to CK treatment. Cell death and the expression of ß-catenin and cyclin D1 were then examined. CK dose- and time-dependently inhibited MCF-7 cell proliferation. Interestingly, CK induced programmed necrosis, but not apoptosis, via the GSK3ß signaling pathway in MCF-7 cells. CK inhibited GSK3ß phosphorylation, thereby suppressing the expression of ß-catenin and cyclin D1. Our results suggest that CK induces programmed necrosis in MCF-7 breast cancer cells via the GSK3ß signaling pathway.

Lon Mutant of Brucella abortus Induces Tumor Necrosis Factor-Alpha in Murine J774.A1 Macrophage.

OBJECTIVES: The objective of this study was to isolate a Brucella lon mutant and to analyze the cytokine response of B. lon mutant during macrophage infection. METHODS: A wild-type Brucella abortus strain was mutagenized by Tn5 transposition. From the mouse macrophage J774.A1 cells, total RNA was isolated at 0 hours, 6 hours, 12 hours, and 24 hours after infection with Brucella. Using mouse cytokine microarrays, we measured transcriptional levels of the cytokine response, and validated our results with a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to confirm the induction of cytokine messenger RNA (mRNA). RESULTS: In host J774.A1 macrophages, mRNA levels of T helper 1 (Th1)-type cytokines, including tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukin-2 (IL-2), and IL-3, were significantly higher in the lon mutant compared to wild-type Brucella and the negative control. TNF-α levels in cell culture media were induced as high as 2 µg/mL after infection with the lon mutant, a greater than sixfold change. CONCLUSION: In order to understand the role of the lon protein in virulence, we identified and characterized a novel B. lon mutant. We compared the immune response it generates to the wild-type Brucella response in a mouse macrophage cell line. We demonstrated that the B. lon mutants induce TNF-α expression from the host J774.A1 macrophage.

Interactions of dendritic cells with cancer cells and modulation of surface molecules affect functional properties of CD8+ T cells.

To understand the interaction of dendritic cells (DCs) with cancer cells, we investigated molecular changes in DCs following co-culture with cancer cells. DCs co-cultured with Jurkat cancer cells showed remarkable down-regulation of MHC class I molecules, while DCs co-cultured with MCF-7 cancer cells showed minimal changes. Interestingly, down-regulation of MHC class I on DCs was not observed upon treatment with Jurkat cell lysate or culture supernatant, suggesting the importance of direct cell-cell interactions. The expressions of CD40, CD80, CD83, MHC class II, and IL-12p40 on DCs co-cultured with Jurkat cells were only slightly affected. In contrast, DCs co-cultured with MCF-7 cells showed increased expressions of CD80, CD83, CD86, and IL-12p40. Furthermore, DCs co-cultured with Jurkat cells showed a down-regulation of low molecular weight polypeptides (LMP) 7, and of transporter associated with antigen processing (TAP) 1 and 2 at the mRNA expression level. LMP7, TAP2 and ß2-microglobulin (ß2M) were also down-regulated at the protein level. We further demonstrated how altered expression of MHC class I on DCs caused by co-culture with cancer cells affected autologous CD8(+) T cells, using the model MHC class I-presented HSV antigen. We found that DCs that had been HSV-treated and co-cultured with Jurkat cells showed a reduced potency to activate CD8(+) T cells. In contrast, HSV-treated DCs that had been co-cultured with MCF-7 cells induced activation of CD8(+) T cells, including high expression of CD25, CD69, granzyme B and cytokines, TNF-α and IFN-γ.

Intranasal immunization with plasmid DNA encoding spike protein of SARS-coronavirus/polyethylenimine nanoparticles elicits antigen-specific humoral and cellular immune responses.

BACKGROUND: Immunization with the spike protein (S) of severe acute respiratory syndrome (SARS)-coronavirus (CoV) in mice is known to produce neutralizing antibodies and to prevent the infection caused by SARS-CoV. Polyethylenimine 25K (PEI) is a cationic polymer which effectively delivers the plasmid DNA. RESULTS: In the present study, the immune responses of BALB/c mice immunized via intranasal (i.n.) route with SARS DNA vaccine (pci-S) in a PEI/pci-S complex form have been examined. The size of the PEI/pci-S nanoparticles appeared to be around 194.7 ± 99.3 nm, and the expression of the S mRNA and protein was confirmed in vitro. The mice immunized with i.n. PEI/pci-S nanoparticles produced significantly (P < 0.05) higher S-specific IgG1 in the sera and mucosal secretory IgA in the lung wash than those in mice treated with pci-S alone. Compared to those in mice challenged with pci-S alone, the number of B220+ cells found in PEI/pci-S vaccinated mice was elevated. Co-stimulatory molecules (CD80 and CD86) and class II major histocompatibility complex molecules (I-Ad) were increased on CD11c+ dendritic cells in cervical lymph node from the mice after PEI/pci-S vaccination. The percentage of IFN-γ-, TNF-α- and IL-2-producing cells were higher in PEI/pci-S vaccinated mice than in control mice. CONCLUSION: These results showed that intranasal immunization with PEI/pci-S nanoparticles induce antigen specific humoral and cellular immune responses.

Alpha-eleostearic acid induces autophagy-dependent cell death through targeting AKT/mTOR and ERK1/2 signal together with the generation of reactive oxygen species.

Alpha-eleostearic acid (alpha-ESA, 9Z11E13E-18:3), a linolenic acid isomer with a conjugated triene system, is a natural and biologically-active compound that has been shown to possess potent anti-tumor properties. Herein, we demonstrate alpha-ESA induced apoptosis and autophagy with reactive oxygen species (ROS) generation in HeLa cells. Treatment with alpha-ESA caused inhibition of phosphorylated (p)AKT and elongated the sub G1 phase in the cell cycle, indicating induction of apoptosis. Autophagy was also induced by alpha-ESA treatment, causing low pAKT and pP70S6K activities, increasing pERK1/2 and leading to a higher conversion rate of LC3 I to LC3 II compared to that of the control. The autophagy was further confirmed by fluorescence microscopy and flow cytometry through monodansylcadavarine (MDC) staining. It appears that the role of autophagy is a protective mechanism against cell death in alpha-ESA-treated HeLa cells. Subsequently, we found that treating HeLa cells with alpha-ESA induced the generation of reactive oxygen species (ROS). The phosphorylation of P70S6K, downstream of mTOR signaling, and AKT were further reduced by pretreatment with N-acetyl-l-cysteine (NAC), an ROS scavenger, whereas the phosphorylation of ERK1/2 and the conversion of LC3 I to LC3 II were further enhanced. As a result, the blocking of the action of ROS promoted alpha-ESA-induced apoptosis and autophagy. Taken together, our results indicate that the generation of ROS by alpha-ESA treatment impedes the progress of apoptosis and excessive autophagy formation which takes part in cell death, thus impeding death promotion.

Exploitation of the endocytic pathway by Orientia tsutsugamushi in nonprofessional phagocytes.

Orientia tsutsugamushi, a causative agent of scrub typhus, is an obligate intracellular bacterium that requires the exploitation of the endocytic pathway in the host cell. We observed the localization of O. tsutsugamushi with clathrin or adaptor protein 2 within 30 min after the infection of nonprofessional phagocytes. We have further confirmed that the infectivity of O. tsutsugamushi is significantly reduced by drugs that block clathrin-mediated endocytosis but not by filipin III, an inhibitor that blocks caveola-mediated endocytosis. In the present study, with a confocal microscope, O. tsutsugamushi was sequentially colocalized with the early and late endosomal markers EEA1 and LAMP2, respectively, within 1 h after infection. The colocalization of O. tsutsugamushi organisms with EEA1 and LAMP2 gradually disappeared until 2 h postinfection, and then free O. tsutsugamushi organisms were found in the cytoplasm. When the acidification of endocytic vesicles was blocked by treating the cells with NH(4)Cl or bafilomycin A, the escape of O. tsutsugamushi organisms from the endocytic pathway was severely impaired, and the infectivity of O. tsutsugamushi was drastically reduced. To our knowledge, this is the first report that the invasion of O. tsutsugamushi is dependent on the clathrin-dependent endocytic pathway and the acidification process of the endocytic vesicles in nonprofessional phagocytes.

Association of herpesvirus saimiri tip with lipid raft is essential for downregulation of T-cell receptor and CD4 coreceptor.

Lipid rafts are membrane microdomains that are proposed to function as platforms for both receptor signaling and trafficking. Our previous studies have demonstrated that Tip of herpesvirus saimiri (HVS), which is a T-lymphotropic tumor virus, is constitutively targeted to lipid rafts and interacts with cellular Lck tyrosine kinase and p80 WD repeat-containing endosomal protein. Through the interactions with Lck and p80, HVS Tip modulates diverse T-cell functions, which leads to the downregulation of T-cell receptor (TCR) and CD4 coreceptor surface expression, the inhibition of TCR signal transduction, and the activation of STAT3 transcription factor. In this study, we investigated the functional significance of Tip association with lipid rafts. We found that Tip expression remarkably increased lipid raft fractions in human T cells by enhancing the recruitment of lipid raft-resident proteins. Genetic analysis showed that the carboxyl-terminal transmembrane, but not p80 and Lck interaction, of Tip was required for the lipid raft localization and that lipid raft localization of Tip was necessary for the efficient downregulation of TCR and CD4 surface expression. Correlated with this, treatment with Filipin III, a lipid raft-disrupting agent, effectively reversed the downregulation of CD3 and CD4 surface expression induced by Tip. On the other hand, Tip mutants that were no longer present in lipid rafts were still capable of inhibiting TCR signaling and activating STAT3 transcription factor activity as efficiently as wild-type (wt) Tip. These results indicate that the association of Tip with lipid rafts is essential for the downregulation of TCR and CD4 surface expression but not for the inhibition of TCR signal transduction and the activation of STAT3 transcription factor. These results also suggest that the signaling and targeting activities of HVS Tip rely on functionally and genetically separable mechanisms, which may independently modulate T-cell function for viral persistence or pathogenesis.