Human Cytomegalovirus (HCMV)-infected Astrocytoma Cells Impair the Function of HCMV-specific Cytotoxic T Cells

Background@#Human cytomegalovirus (HCMV) infection in glioblastoma multiforme (GBM) is associated with a poor prognosis and may affect the pathogenesis of GBM. In this study, we investigated the role of HCMV-infected astrocytoma cells in impairing the activity of cytotoxic T lymphocytes (CTLs) specific to the HCMV protein. @*Methods@#CTLs specific to HCMV immediate early (IE)-1 were expanded from peripheral blood mononuclear cells of healthy donors by stimulating CD8+ T lymphocytes with U373MG cells (ATCC HTB-17: male) expressing HCMV IE-1. The death rate of the target and the effector cells was determined by the total count of the remaining respective cells after the interaction of them. @*Results@#The death rate of the target cells by CTLs increased depending on HLA restriction and the effector:target (E:T) ratio. The death rate of effector cells in the HCMV-infected U373MG cell culture was 37.1% on day 4 post-infection. The removal of the culture supernatant from HCMV-infected U373MG cells prior to adding the effector cells increased target cell death from 8.4% to 40.8% at E:T = 1:1, but not at E:T = 3:1. The transfer of cells from a 24-hour co-culture of the HCMV-infected U373MG cells and CTLs to HCMV IE-1-expressing target cells resulted in decreasing the cell death rate of the target cells from 31.1% to 13.0% at E:T = 1:1, but not at E:T = 3:1. HCMV infection of U373MG cells decreases the activity of CTLs specific to HCMV when the number of CTLs is low. @*Conclusion@#These results suggest that HCMV could impair CTL activity and facilitate glioblastoma growth unchecked by CTLs.

Rapid Whole-genome Sequencing of Zika Viruses using Direct RNA Sequencing

Zika virus (ZIKV) is one of the pathogens which is transmitted world widely, but there are no effective drugs and vaccines. Whole genome sequencing (WGS) of viruses could be applied to viral pathogen characterization, diagnosis, molecular surveillance, and even finding novel pathogens. We established an improved method using direct RNA sequencing with Nanopore technology to obtain WGS of ZIKV, after adding poly (A) tails to viral RNA. This established method does not require specific primers, complimentary DNA (cDNA) synthesis, and polymerase chain reaction (PCR)-based enrichment, resulting in the reduction of biases as well as of the ability to find novel RNA viruses. Nanopore technology also allows to read long sequences. It makes WGS easier and faster with long-read assembly. In this study, we obtained WGS of two strains of ZIKV following the established protocol. The sequenced reads resulted in 99% and 100% genome coverage with 63.5X and 21,136X, for the ZIKV PRVABC59 and MR 766 strains, respectively. The sequence identities of the ZIKV PRVABC59 and MR 766 strains for each reference genomes were 98.76% and 99.72%, respectively. We also found that the maximum length of reads was 10,311 bp which is almost the whole genome size of ZIKV. These long-reads could make overall structure of whole genome easily, and WGS faster and easier. The protocol in this study could provide rapid and efficient WGS that could be applied to study the biology of RNA viruses including identification, characterization, and global surveillance.

World Outbreak Trend of Infectious Diseases with Surveillance

The diverse infectious diseases can occur everywhere in the world, but high-risk infectious diseases should be monitored immediately after the occurrence, and be controlled not to spread to the public. Other highly contagious ones also should be screened with the surveillance system and made to be prevented from a serious effect on public health. The outbreak information, articles and news reports concerning global infectious disease outbreaks were collected from known web-based resources and deposited in Global Center for Infectious Diseases since 2016. The number of reports collected from various sources was analyzed on the respect of Blueprint priority diseases and vaccine-preventable diseases, and the characteristic outbreak trend was shown in the geographic distribution and the so-called socio-economic level of countries. The WHO R&D Blueprint priority diseases are being reported especially in the region of Africa and Asia. The vaccine-preventable and other infectious diseases also are reported continuously and world-widely. They threaten the safety of life continuously in public. Therefore, keeping close observation and strengthening infectious disease surveillance is needed, and more effort to expand the collecting resources to get more outbreak information is warranted.

Changes of Epidemiological Characteristics of Japanese Encephalitis Viral Infection and Birds as a Potential Viral Transmitter in Korea

Japanese encephalitis (JE) cases have been increasingly reported recently especially in Seoul and its vicinity. Pigs are known as amplifying host of JE virus (JEV), but do not play an important role in these recent events because pig-breeding is not common in Seoul. The distribution and the density of migratory birds are correlated with JE cases in cities and they might be highly potential hosts contributing to transmit JEV in metropolitan areas. JE genotype and sero-prevalence in birds should be determined for the verification of the transmission route of JEV in the recent sporadic occurrence of JE cases in Seoul.

An Urgent Need for Global Preparedness against the Reemergence of “Forgotten” Infectious Diseases in Korea

No abstract available.

Epidemiological Characteristics and Risk Factors of Dengue Infection in Korean Travelers

Dengue viral infection has rapidly spread around the world in recent decades. In Korea, autochthonous cases of dengue fever have not been confirmed yet. However, imported dengue cases have been increased since 2001. The risk of developing severe dengue in Korean has been increased by the accumulation of past-infected persons with residual antibodies to dengue virus and the remarkable growth of traveling to endemic countries in Southeast Asia. Notably, most of imported dengue cases were identified from July to December, suggesting that traveling during rainy season of Southeast Asia is considered a risk factor for dengue infection. Analyzing national surveillance data from 2011 to 2015, males aged 20–29 years are considered as the highest risk group. But considering the age and gender distribution of travelers, age groups 10–49 except 20–29 years old males have similar risks for infection. To minimize a risk of dengue fever and severe dengue, travelers should consider regional and seasonal dengue situation. It is recommended to prevent from mosquito bites or to abstain from repetitive visit to endemic countries. In addition, more active surveillance system and monitoring the prevalence asymptomatic infection and virus serotypes are required to prevent severe dengue and indigenous dengue outbreak.

The Preparedness for Re-emerged and Emerging Infectious Diseases: A Lesson Through Outbreak of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in South Korea

The Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe acute respiratory disease and systemic dysfunction that may eventually lead to the death of the patients. After MERS-CoV was first diagnosed in the South Korea, in May 2015, it affected 186 individuals and claimed 37 lives in short span of time (case fatality rate = 19.9%). Compared to MERS-CoV in the Middle East, MERS-CoV in South Korea appeared to be more transmissible, and induced multiple human-to-human transmission. These knowledge gaps caused the failure of early prevention, and disseminated MERS-CoV brought out a great loss of lives and economy. The MERS-CoV outbreak revealed the potential weakness of public health system in South Korea, and promoted the reestablishment of preventive strategies for imported infectious diseases. In these regards, we analyzed the potential for additional import of re-emerged and emerging infectious diseases, such as dengue fever, malaria, chikungunya fever and hepatitis A, from Africa or South-East Asia. Then we suggest the investment expansion and the administration of global networks for effective research and control for newly or re-emerged infectious diseases. In conclusion, it is required to expect and prepare for the surveillance of the importation of foreign pathogens, and constitute the internal collaborative systems for rapid detection and risk communication. In addition, we should take an active part in the global networks to perform rapid preparedness and control for re-emerged or emerging infectious diseases.

Nucleotide Binding Oligomerization Domain 1 Is an Essential Signal Transducer in Human Epithelial Cells Infected with Helicobacter pylori That Induces the Transepithelial Migration of Neutrophils

BACKGROUND/AIMS: The cytosolic host protein nucleotide binding oligomerization domain 1 (Nod1) has emerged as a key pathogen recognition molecule for innate immune responses in epithelial cells. The purpose of the study was to elucidate the mechanism by which Helicobacter pylori infection leads to transepithelial neutrophil migration in a Nod1-mediated manner. METHODS: Human epithelial cell lines AGS and Caco-2 were grown and infected with H. pylori. Interleukin (IL)-8 mRNA expression and IL-8 secretion were assessed, and nuclear factor kappaB (NF-kappaB) activation was determined. Stable transfections of AGS and Caco-2 cells with dominant negative Nod1 were generated. Neutrophil migration across the monolayer was quantified. RESULTS: Cytotoxin-associated gene pathogenicity island (cagPAI)(+) H. pylori infection upregulated IL-8 mRNA expression and IL-8 secretion in AGS and Caco-2 cells compared with controls. NF-kappaB activation, IL-8 mRNA expression and IL-8 secretion by cagPAI knockdown strains were reduced compared with those infected with the wild-type strain. NF-kappaB activation, IL-8 mRNA expression and IL-8 secretion in dominant-negative (DN)-Nod1 stably transfected cells were reduced compared with the controls. The transepithelial migration of neutrophils in DN-Nod1 stably transfected cells was reduced compared with that in controls. CONCLUSIONS: Signaling through Nod1 plays an essential role in neutrophil migration induced by the upregulated NF-kappaB activation and IL-8 expression in H. pylori-infected human epithelial cells.

Distribution of Human Rotavirus Genotypes in a Tertiary Hospital, Seoul, Korea During 2009-2013

PURPOSE: Group A rotavirus (RV) is most common etiologic agent of acute gastroenteritis (AGE) in children worldwide. Recently, vaccination has been introduced in several countries to reduce the disease burden caused by RV infections, but continuous surveillance of RV strains is necessary to detect the emergence of potential variants induced by vaccine-immune pressure. This study aimed to investigate the changing pattern of RV genotypes in children with AGE, following the introduction of vaccination in Korea. METHODS: Genotyping of RVs by RT-PCR on the basis of VP7 and VP4 gene segment sequence was carried out on 201 rotavirus-positive stool samples, from children hospitalized with AGE between August 2009 and June 2013. We have directly sequenced PCR products and analyzed the phylogenetic tree. RESULTS: The most prevalent G genotype was G9 (33.3%), followed by G1 (22.4%), G3 (15.9%), G2 (6.0%), G4 (3.0%), G10 (1.5%), and mixed G-type (15.4%), with some nontypeable cases (2.5%). The detected P genotypes were P[4] (45.3%), P[8] (43.8%), mixed P-type (10.4%), and P[2] (0.5%). The G9P[4] genotype was predominantly observed in hospitalized cases in Seoul in 2010/2011, however G1P[8] has been re-emerged as the predominant genotype in the following season (P=0.004). CONCLUSIONS: It seems that the periodic fluctuation in predominance of the G1, G3, and G9 strains occurred in Korea during 2009-2013, following the introduction of RV vaccination.

Analysis of env Subtypes of Porcine Endogenous Retrovirus in SNU Miniature Pigs

All xenografts from pigs impose infection risk by porcine endogenous retrovirus (PERV). The purpose of this study was to investigate the env constructs with the comparison of the ratio of the competent form to the defective one of env in subtypes, PERV-A, PERV-B and PERV-C in different pig breeds. The results of PCR amplification of env represented that all env subtypes had more than two defective forms which cannot bind to host cells due to the absence of binding regions of env in miniature pigs, SNU and PWG, and farm pig breeds, Duroc, Yorkshire and Landrace. In addition, comparing the full sequences with the defective ones in three subtypes demonstrated that the present percentages of env sequences in defective PERV-A, PERV-B and PERV-C were approximately 50%, 38~45% and 4~11%, respectively, in SNU and PWG pigs whereas PERV-A and PERV-B occupied around 40 to 60% but PERV-C was not detected in farm pigs. Quantitative real-time PCR assays with primers and probes targeted to proline-rich region (PRR) of each env subtype were done to measure the copy numbers of each env subtype. When the reference was set with copy number of PERV-A, the ratio of those of PERV-B and PERV-C to the reference were 1.5 to 6.0 folds high in SNU and PWG pigs while 1.0 or less in farm pigs. These contradictory results of PERV-C constructs and copy numbers in SNU pigs suggests that many truncated or short defective sequences of PERV-C might be present in them.

Preparedness for Prevention of Ebola Virus Disease

No abstract available.

Preparedness for Prevention of Ebola Virus Disease

No abstract available.

Cytoplasmic Translocation of p53 by Human Cytomegalovirus Infection

p53 is a well-known multi-functional transcription regulator and is critical in the induction of apoptosis in response to various stresses. Human cytomegalovirus (HCMV) infection induced the accumulation of p53, which was partly relocalized in cytoplasm, but no apparent cell death in human fibroblasts. p53 in HCMV-infected cells was mainly mono-ubiquitinated, which might be resulted from the decreased expression of MDM2 in the course of HCMV infection. Ubiquitinated p53 was also phosphorylated at serine 20. CRM1 increased in the cytoplasm of HCMV-infected cells. It was found that p53 and its mutant in nuclear export sequences were localized in the cytoplasm of cells when co-expressed with CRM1. Collectively, our data suggest that HCMV infection modifies p53 into a stable and exportable form and accumulates it in the cytoplasm, but does not result in apoptotic death of cells.

Detection of Adeno-associated Virus from Semen Suffering with Male Factor Infertility and Having Their Conception Partners with Recurrent Miscarriages

Adeno-associated virus (AAV) and human papillomavirus (HPV) DNAs were found in abnormal quality semen, early abortus and female genital tissues. It was suggested that they might cause male infertility and miscarriages. This study was performed to determine the detection rate of these viruses in the semen and to assess the relationship between the presence of virus and male factor infertility and recurrent miscarriages. Sixty-three of 99 recruited male were included in this study according to the completeness of follow-up and the sample availability. Fourteen male with normal reproductive capacity were allocated to control group, 15 male with abnormal results in semen analysis were grouped as male factor infertility (MF) group, and 34 male whose spouses have had history of repeated spontaneous abortions were designated as repeated miscarriage (RM) group. AAV and HPV were detected in semen by polymerase chain reaction. The detection rate of AAV in the MF infertility group and RM group was 60.0% and 50.0%, respectively, while 14.3% in the control group (p < 0.05). However, the differences in the detection rate of HPV were not statistically significant among groups. These results suggest that AAV could be related to repeated miscarriages and male infertility.

Detection of Human Cytomegalovirus (HCMV) and Porcine Endogenous Retrovirus (PERV) with One Step Extraction Method

BACKGROUND: Xenotransplantation is thought to be one of the alternative methods to overcome the shortage of human organs for transplantation. Recipients should be immunosuppressed for graft survival, and thus, there is a need for developing diagnostic modality that can detect diverse infections originating from animals and recipients rapidly, in the early stage, and with high sensitivity using small volume of samples. This study was carried out to develop a fast, simple, and robust technique for the preparation of HCMV DNA and PERV RNA using small volume of samples. MATERIALS AND METHODS: Nucleic acids were extracted from serially diluted samples with one step extraction method as well as with Qiagen kit. The presence of genomic DNA of human cytomegalovirus (HCMV) and porcine endogenous retrovirus (PERV) was detected by PCR and specific primer set, respectively. RNA of HCMV and PERV was extracted and then detected by RT-PCR and specific primer set, respectively. For absolute quantification of HCMV, standard curve was established by real time PCR. RESULTS: HCMV DNA and PERV RNA were prepared from culture supernatant and cells for PCR or RT-PCR with one step extraction method. It was possible to extract both the DNA and RNA from the samples in about 20 minutes with one step extraction method in a single tube. HCMV and PERV could also be detected by PCR and one step extraction method, respectively. It was also good with small quantity samples. CONCLUSIONS: One step extraction method is simpler and faster method than other extraction methods when there are two types of DNA and RNA viruses in one sample. From these results, we could see that the one step extraction method could be very useful in detecting HCMV and PERV rapidly from the pig cells or organ transplanted recipients with a small amount of sample.

No Evidence of the Productive Replication of Porcine Endogenous Retrovirus (PERV) from SNU Miniature Pigs in Human Cell Line

BACKGROUND: The presence of porcine endogenous retrovirus (PERV) has been considered as one of the main hurdles to transplant pig's organs or tissues to human beings. There has been no report that PERV infection is associated with human diseases. Because pigs have their own characteristics of PERV according to pig strain, it is necessary to analyze the infectivity of PERV from SNU miniature pig to human cells for future utilization as a transplantation donor. MATERIALS AND METHODS: Human cell lines were infected with culture supernatant from porcine cell line or immunomodulator-stimulated peripheral blood mononuclear cells (PBMC) of SNU miniature pigs. They were also co-cultured with PBMC or islet cells of SNU miniature pigs. The presence of PERV genes and general pig marker gene in cells was determined by nested PCR with primer set for PERV pol and pig mitochondrial cytochrome oxidase II (COII), respectively. RESULTS: Infection test with the culture supernatant from PBMC of SNU miniature pigs showed that PERV pol but not COII was detected only in a few cases, but there was no uniform infection pattern in scope of stimulators and cell types. PERV pol was not demonstrated in co-cultures of human cell line with PBMC or islet cells from SNU miniature pigs after 80 days of co-cultures. CONCLUSIONS: In vitro infectivity test suggests that PERV from SNU miniature pig might not replicate productively in human cell lines although it could infect human cells and integrate into chromosome.

Characterization of Clones of Human Cell Line Infected with Porcine Endogenous Retrovirus (PERV) from Porcine Cell Line, PK-15

BACKGROUND: Porcine endogenous retroviruses (PERVs) form part of the chromosomes of all pigs. Since they can be produced as infectious virion and infect human cells, safety issues on PERVs infection to human are still controversial and is one of main hurdles of xenotransplantation using pig cells or organs. It has been reported that the established porcine cell line, PK-15, produces PERVs and can infect the human cell lines. Therefore, clonal analysis on human cell line infected with PERV is a prerequisite to characterize the infectivity to human cells and to investigate the harmfulness of PERVs to human. MATERIALS AND METHODS: For the characterization of PERV that originates from porcine cell line, PK-15, full length PERV cloning from genomic DNA of PK-15 was performed and partial sequences of both ends were achieved. Cell clones from human cell line, 293, persistently infected with PERVs from PK-15 were established by the method of limiting dilution. Nested PCR and direct sequencing of PCR products in each clone were carried out so as to confirm the PERV genomes in each clone. The growth rate of each clone was checked using cell counting and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, the infectivity by reverse transcriptase (RT) assay, and genetic analysis by karyotyping. RESULTS: A total of 12 genomic PERV clones could be retrieved; 1 with full length, 4 with defective forms, and others with irrelevant sequences. Intact PERV was thought to be able to infect 293 and the PERV-infected cell clones were selected by limiting dilution. PCR results confirmed that nine cell clones were infected with PERV, and sequence alignment data on PCR products of pol region from PK-15 and human cell clones with PERV showed very similar results. Cell counting and MTT assay for growth kinetics of each clone indicated that two clones showed reduced growth rate. However, it was difficult to verify the effect of PERV infection on the cell growth because of the presence of many genetic alterations in 293 parental cells. No RT activities were detected in the culture supernatant from PERV-infected 293 cell clones. CONCLUSION: The sequences of PERVs were detected in human cell clones after PERV infection, but PERV virions could not be detected from the culture supernatant by RT assay.

Characterization of Clones of Human Cell Line Infected with Porcine Endogenous Retrovirus (PERV) from Porcine Cell Line, PK-15

BACKGROUND: Porcine endogenous retroviruses (PERVs) form part of the chromosomes of all pigs. Since they can be produced as infectious virion and infect human cells, safety issues on PERVs infection to human are still controversial and is one of main hurdles of xenotransplantation using pig cells or organs. It has been reported that the established porcine cell line, PK-15, produces PERVs and can infect the human cell lines. Therefore, clonal analysis on human cell line infected with PERV is a prerequisite to characterize the infectivity to human cells and to investigate the harmfulness of PERVs to human. MATERIALS AND METHODS: For the characterization of PERV that originates from porcine cell line, PK-15, full length PERV cloning from genomic DNA of PK-15 was performed and partial sequences of both ends were achieved. Cell clones from human cell line, 293, persistently infected with PERVs from PK-15 were established by the method of limiting dilution. Nested PCR and direct sequencing of PCR products in each clone were carried out so as to confirm the PERV genomes in each clone. The growth rate of each clone was checked using cell counting and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, the infectivity by reverse transcriptase (RT) assay, and genetic analysis by karyotyping. RESULTS: A total of 12 genomic PERV clones could be retrieved; 1 with full length, 4 with defective forms, and others with irrelevant sequences. Intact PERV was thought to be able to infect 293 and the PERV-infected cell clones were selected by limiting dilution. PCR results confirmed that nine cell clones were infected with PERV, and sequence alignment data on PCR products of pol region from PK-15 and human cell clones with PERV showed very similar results. Cell counting and MTT assay for growth kinetics of each clone indicated that two clones showed reduced growth rate. However, it was difficult to verify the effect of PERV infection on the cell growth because of the presence of many genetic alterations in 293 parental cells. No RT activities were detected in the culture supernatant from PERV-infected 293 cell clones. CONCLUSION: The sequences of PERVs were detected in human cell clones after PERV infection, but PERV virions could not be detected from the culture supernatant by RT assay.

Human Cytomegalovirus IE1 Protein Enhances Herpes Simplex Virus Type 1-induced Syncytial Formation in U373MG Cells

Co-infection of herpes simplex virus type 1 (HSV-1) and human cytomegalovirus (HCMV) is not uncommon in immunocompromised hosts. Importantly, organ transplant recipients concurrently infected with HSV-1 and HCMV have a worse clinical outcome than recipients infected with a single virus. However, factors regulating the pathologic response in HSV-1, HCMV co-infected tissues are unclear. We investigated the potential biologic role of HCMV gene product immediate early 1 (IE1) protein in HSV-1-induced syncytial formation in U373MG cells. We utilized a co-infection model by infecting HSV-1 to U373MG cells constitutively expressing HCMV IE1 protein, UMG1-2. Syncytial formation was assessed by enumerating nuclei number per syncytium and number of syncytia. HSV-1-induced syncytial formation was enhanced after 24 hr in UMG1-2 cells compared with U373MG controls. The amplified phenotype in UMG1-2 cells was effectively suppressed by roscovitine in addition to inhibitors of viral replication. This is the first study to provide histological evidence of the contribution of HCMV IE1 protein to enhanced cytopathogenic responses in active HSV-1 infection.

Distribution of Human Cytomegalovirus gB Genotypes and Its Association with Diseases in Hematopoietic Stem Cell Transplant Recipients in Korea; A Preliminary Report

BACKGROUND: Human cytomegalovirus (HCMV) glycoprotein B (gB) is the major envelope glycoprotein, encoded by the UL55 gene. Based on sequence variation in the UL55 gene, HCMV can be classified into four gB genotypes. Previous studies have suggested an association between HCMV gB genotypes and clinical outcome in the immunocompromised hosts. The goal of this study was to determine the distribution of HCMV gB genotypes and the effect of gB genotype in the developement of HCMV diseases in hematopoietic stem cell transplant (HSCT) recipients in Korea. MATERIALS AND METHODS: DNA was extracted from 94 blood specimen of 52 allogeneic HSCT recipients with HCMV infection. HCMV gB genotype was determined using polymerase chain reaction to amplify a region of UL55, followed by restriction fragment length polymorphism (RFLP) analysis based on RsaI and HinfI digestion. RESULTS: The distribution of gB types were as follows: gB1, 73.1% (38/52) of patients; gB2, 13.5% (7/52); gB3, 1.9% (1/52) and mixed infection (gB1 and gB2), 9.6% (5/52). While gB4 was not detected, a new genotype (described as gB7 by Trincado et al, 2000) was identified on the basis of their RFLP pattern. During average 708 days' follow up period, HCMV diseases developed in 5 patients. All of them had gB1 genotype. There was no statistically significant association between the incidence of HCMV diseases and the gB genotypes. Re-infection with gB1 strain was detected in one patient who had been previously infected with gB2. This episode was associated with fever, elevated liver enzyme and positive antigenemia. CONCLUSION: HCMV gB1 was the dominant genotype and no gB4 was detected in allogeneic HSCT recipients in Korea, which is an unique pattern compared with the previous reports. Although we can not find significant association between the HCMV diseases and the gB genotypes, genotyping of HCMV will serve in the study of pathogenesis and transmission of this virus in transplant patients. Further study is underway with large study population.