A candidate gene approach of immune mediators effecting the susceptibility to and severity of upper gastrointestinal tract diseases in relation to Helicobacter pylori and Epstein-Barr virus infections

Development of a murine model for aerosolized ebolavirus infection using a panel of recombinant inbred mice

Countering aerosolized filovirus infection is a major priority of biodefense research. Aerosol models of filovirus infection have been developed in knock-out mice, guinea pigs and non-human primates; however, filovirus infection of immunocompetent mice by the aerosol route has not been reported. A murine model of aerosolized filovirus infection in mice should be useful for screening vaccine candidates and therapies. In this study, various strains of wild-type and immunocompromised mice were exposed to aerosolized wild-type (WT) or mouse-adapted (MA) Ebola virus (EBOV). Upon exposure to aerosolized WT-EBOV, BALB/c, C57BL/6 (B6), and DBA/2 (D2) mice were unaffected, but 100% of severe combined immunodeficiency (SCID) and 90% of signal transducers and activators of transcription (Stat1) knock-out (KO) mice became moribund between 7–9 days post-exposure (dpe). Exposure to MA-EBOV caused 15% body weight loss in BALB/c, but all mice recovered. In contrast, 10–30% lethality was observed in B6 and D2 mice exposed to aerosolized MA-EBOV, and 100% of SCID, Stat1 KO, interferon (IFN)-γ KO and Perforin KO mice became moribund between 7–14 dpe. In order to identify wild-type, inbred, mouse strains in which exposure to aerosolized MA-EBOV is uniformly lethal, 60 BXD (C57BL/6 crossed with DBA/2) recombinant inbred (RI) and advanced RI (ARI) mouse strains were exposed to aerosolized MA-EBOV, and monitored for disease severity. A complete spectrum of disease severity was observed. All BXD strains lost weight but many recovered. However, infection was uniformly lethal within 7 to 12 days post-exposure in five BXD strains. Aerosol exposure of these five BXD strains to 10-fold less MA-EBOV resulted in lethality ranging from 0% in two strains to 90–100% lethality in two strains. Analysis of post-mortem tissue from BXD strains that became moribund and were euthanized at the lower dose of MA-EBOV, showed liver damage in all mice as well as lung lesions in two of the three strains. The two BXD strains that exhibited 90–100% mortality, even at a low dose of airborne MA-EBOV will be useful mouse models for testing vaccines and therapies. Additionally, since disease susceptibility is affected by complex genetic traits, a systems genetics approach was used to identify preliminary gene loci modulating disease severity among the panel BXD strains. Preliminary quantitative trait loci (QTLs) were identified that are likely to harbor genes involved in modulating differential susceptibility to Ebola infection.

Epstein-Barr virus-associated gastric carcinoma: a newly defined entity

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is a recently recognized entity, which is defined by the presence of EBV in the gastric carcinoma cells. EBVaGC represents about 10% of gastric carcinoma worldwide, and >80,000 patients are estimated to develop EBVaGC annually. EBVaGC shows some distinct clinicopathologic characteristics, such as male predominance, predisposition to the proximal stomach, and a high proportion in diffuse-type gastric carcinomas. Besides, EBVaGC also shows characteristic molecular abnormality, that is, global and nonrandom CpG-island methylation of the promoter region of many cancer-related genes, which causes downregulation of their expression. Moreover, EBVaGC has a relative favorable prognosis. The uniform presence of EBV-encoded small RNA in tumor cells but not in the surrounding normal epithelial cells, and the detection of monoclonal EBV episomes in EBVaGC, strongly suggests that EBV play an etiological role in gastric carcinogenesis. Therefore, EBVaGC should be regarded as a distinct entity of gastric carcinoma, although it only accounts for a relatively small fraction of total gastric carcinomas. In this review, the epidemiological and clinicopathologic features of EBVaGC and the genetic abnormalities of EBVaGC cell including chromosomal and epigenetic abnormalities are described. The roles of EBV in gastric carcinogenesis are discussed. We make an emphasis on the EBV latency pattern and genome polymorphisms as well as local immunity in EBVaGC. In addition, the treatment of EBVaGC is also briefly discussed. Taken together, this review aims to give the reader a full understanding of a newly defined entity of gastric carcinoma, EBVaGC.

Epstein-Barr virus antibody level and gastric cancer risk in Korea: a nested case-control study

Background:

Few cohort studies have investigated Epstein–Barr virus (EBV) infection before the occurrence of gastric cancer.

Methods:

Among 14 440 cohort participants, 100 incident gastric cancer cases were individually matched to two controls. Epstein–Barr virus antibodies IgG and IgA against viral capsid antigen (VCA), EBV nuclear antigen (EBNA) antibody IgG, and early antigen (EA) antibody IgG were measured using enzyme immunoassays (EIAs).

Results:

The highest titres of VCA IgG (odds ratio (OR): 1.37, 95% confidence interval (CI): 0.62–3.06) or EBNA IgG (OR: 0.87, 95% CI: 0.51–1.46) were not associated with gastric cancer risk.

Conclusion:

Higher levels of VCA IgG or EBNA IgG were not associated with increased risk of gastric adenocarcinoma in Koreans.

Joint effect between regular use of non-steroidal anti-inflammatory drugs, variants in inflammatory genes and risk of lymphoma

OBJECTIVE

Limited evidence suggests the importance of inflammatory processes for the etiology of lymphomas. To further research in this area, we investigated the role of genetic variants in key inflammatory factors, non-steroidal anti-inflammatory drug [NSAID] use, and their joint effect in lymphomagenesis.

METHODS

The study comprised 710 case-control pairs, matched for gender, age, and study region. We examined the association of regular NSAID use and polymorphisms in prostaglandin-endoperoxide synthase-2 (COX2), prostaglandin E synthase (PTGES), interleukin-1 alpha (IL1A), IL-1 beta (IL1B), and IL-1 receptor antagonist (IL1RA), and lymphoma risk by applying logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Regular NSAID use was associated with a slightly reduced risk of B-NHL (OR = 0.8, 95% CI = 0.6-1.1). For T-NHL, the COX2 rs2745557 A-allele conferred a 2.2-fold (95% CI = 1.1-4.5) and homozygosis for the IL1RN rs454078 T-allele was associated with a 4.5-fold (95% CI = 1.4-13.9) elevated risk, however, based on sparse data. IL1 haplotype 5 was associated with a statistically significant 43% increased risk for B-NHL among non-regular users of NSAIDs, but a 70% decreased risk for regular users (p-value for interaction < 0.001).

CONCLUSIONS

These results suggest the relevance of joint effects between NSAID use and IL1 haplotypes on the risk of B-NHL.

Susceptibility to severe Streptococcal sepsis: use of a large set of isogenic mouse lines to study genetic and environmental factors

Variation in responses to pathogens is influenced by exposure history, environment and the host's genetic status. We recently demonstrated that human leukocyte antigen class II allelic differences are a major determinant of the severity of invasive group A streptococcal (GAS) sepsis in humans. While in-depth controlled molecular studies on populations of genetically well-characterized humans are not feasible, it is now possible to exploit genetically diverse panels of recombinant inbred BXD mice to define genetic and environmental risk factors. Our goal in this study was to standardize the model and identify genetic and nongenetic covariates influencing invasive infection outcomes. Despite having common ancestors, the various BXD strains (n strains=33, n individuals=445) showed marked differences in survival. Mice from all strains developed bacteremia but exhibited considerable differences in disease severity, bacterial dissemination and mortality rates. Bacteremia and survival showed the expected negative correlation. Among nongenetic factors, age -- but not sex or weight -- was a significant predictor of survival (P=0.0005). To minimize nongenetic variability, we limited further analyses to mice aged 40-120 days and calculated a corrected relative survival index that reflects the number of days an animal survived post-infection normalized to all significant covariates. Genetic background (strain) was the most significant factor determining susceptibility (P< or =0.0001), thus underscoring the strong effect of host genetic variation in determining susceptibility to severe GAS sepsis. This model offers powerful unbiased forward genetics to map specific quantitative trait loci and networks of pathways modulating the severity of GAS sepsis.