99th Dahlem conference on infection, inflammation and chronic inflammatory disorders: symbionts and immunopathology in chronic diseases: insights from evolution

Unlocking the Role of a Genital Herpesvirus, Otarine Herpesvirus 1, in California Sea Lion Cervical Cancer

Urogenital carcinoma in California sea lions (Zalophus californianus) is the most common cancer of marine mammals. Primary tumors occur in the cervix, vagina, penis, or prepuce and aggressively metastasize resulting in death. This cancer has been strongly associated with a sexually transmitted herpesvirus, otarine herpesvirus 1 (OtHV1), but the virus has been detected in genital tracts of sea lions without cancer and a causative link has not been established. To determine if OtHV1 has a role in causing urogenital carcinoma we sequenced the viral genome, quantified viral load from cervical tissue from sea lions with (n = 95) and without (n = 163) urogenital carcinoma, and measured viral mRNA expression using in situ mRNA hybridization (Basescope®) to quantify and identify the location of OtHV1 mRNA expression. Of the 95 sea lions diagnosed with urogenital carcinoma, 100% were qPCR positive for OtHV1, and 36% of the sea lions with a normal cervix were positive for the virus. The non-cancer OtHV1 positive cases had significantly lower viral loads in their cervix compared to the cervices from sea lions with urogenital carcinoma. The OtHV1 genome had several genes similar to the known oncogenes, and RNA in situ hybridization demonstrated high OtHV1 mRNA expression within the carcinoma lesions but not in normal cervical epithelium. The high viral loads, high mRNA expression of OtHV1 in the cervical tumors, and the presence of suspected OtHV1 oncogenes support the hypothesis that OtHV1 plays a significant role in the development of sea lion urogenital carcinoma.

The Modulation of Apoptotic Pathways by Gammaherpesviruses

Apoptosis or programmed cell death is a tightly regulated process fundamental for cellular development and elimination of damaged or infected cells during the maintenance of cellular homeostasis. It is also an important cellular defense mechanism against viral invasion. In many instances, abnormal regulation of apoptosis has been associated with a number of diseases, including cancer development. Following infection of host cells, persistent and oncogenic viruses such as the members of the Gammaherpesvirus family employ a number of different mechanisms to avoid the host cell’s “burglar” alarm and to alter the extrinsic and intrinsic apoptotic pathways by either deregulating the expressions of cellular signaling genes or by encoding the viral homologs of cellular genes. In this review, we summarize the recent findings on how gammaherpesviruses inhibit cellular apoptosis via virus-encoded proteins by mediating modification of numerous signal transduction pathways. We also list the key viral anti-apoptotic proteins that could be exploited as effective targets for novel antiviral therapies in order to stimulate apoptosis in different types of cancer cells.

Cancer Evolution-Development: experience of hepatitis B virus-induced hepatocarcinogenesis

Here, we present the basic concept and theoretical framework of a scientific hypothesis called Cancer Evolution-Development ("Cancer Evo-Dev"), based on our recent studies of the molecular mechanisms by which chronic infection with the hepatitis B virus induces hepatocarcinogenesis, together with related advances in that field. Several aspects central to our hypothesis are presented: ■ Immune imbalance-caused by the interaction of genetic predispositions and environmental exposures such as viral infection-is responsible for the maintenance of chronic non-resolving inflammation. Non-resolving inflammation promotes the occurrence and progression of cancers, characterized by an evolutionary process of "mutation-selection-adaptation" for both viruses and host cells.■ Under a microenvironment of non-resolving inflammation, proinflammatory factors promote mutations in viral or host genomes by transactivation of the expression of cytidine deaminases and their analogues. Most cells with genomic mutations and mutated viruses are eliminated in the competition for survival in the inflammatory microenvironment. Only a small percentage of the mutated cells that alter their survival signal pathways and exhibit the characteristics of "stem-ness" can survive and function as cancer-initiating cells.■ Cancers generally develop with properties of "backward evolution" and "retro-differentiation," indicating the indispensability of stem-like signal pathways in the evolution and development of cancers. The hypothesis of Cancer Evo-Dev not only lays the theoretical foundation for understanding the mechanisms by which inflammation promotes the development of cancers, but also plays an important role in specific prophylaxis, prediction, early diagnosis, and targeted treatment of cancers.

The Role of Gammaherpesviruses in Cancer Pathogenesis

Worldwide, one fifth of cancers in the population are associated with viral infections. Among them, gammaherpesvirus, specifically HHV4 (EBV) and HHV8 (KSHV), are two oncogenic viral agents associated with a large number of human malignancies. In this review, we summarize the current understanding of the molecular mechanisms related to EBV and KSHV infection and their ability to induce cellular transformation. We describe their strategies for manipulating major cellular systems through the utilization of cell cycle, apoptosis, immune modulation, epigenetic modification, and altered signal transduction pathways, including NF-kB, Notch, Wnt, MAPK, TLR, etc. We also discuss the important EBV latent antigens, namely EBNA1, EBNA2, EBNA3’s and LMP’s, which are important for targeting these major cellular pathways. KSHV infection progresses through the engagement of the activities of the major latent proteins LANA, v-FLIP and v-Cyclin, and the lytic replication and transcription activator (RTA). This review is a current, comprehensive approach that describes an in-depth understanding of gammaherpes viral encoded gene manipulation of the host system through targeting important biological processes in viral-associated cancers.

Mitigating amphibian chytridiomycosis with bioaugmentation: characteristics of effective probiotics and strategies for their selection and use

Probiotic therapy through bioaugmentation is a feasible disease mitigation strategy based on growing evidence that microbes contribute to host defences of plants and animals. Amphibians are currently threatened by the rapid global spread of the pathogen, Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis. Bioaugmentation of locally occurring protective bacteria on amphibians has mitigated this disease effectively in laboratory trials and one recent field trial. Areas still naïve to Bd provide an opportunity for conservationists to proactively implement probiotic strategies to prevent further amphibian declines. In areas where Bd is endemic, bioaugmentation can facilitate repatriation of susceptible amphibians currently maintained in assurance colonies. Here, we synthesise the current research in amphibian microbial ecology and bioaugmentation to identify characteristics of effective probiotics in relation to their interactions with Bd, their host, other resident microbes and the environment. To target at-risk species and amphibian communities, we develop sampling strategies and filtering protocols that result in probiotics that inhibit Bd under ecologically relevant conditions and persist on susceptible amphibians. This filtering tool can be used proactively to guide amphibian disease mitigation and can be extended to other taxa threatened by emerging infectious diseases.

Broadening the translational immunology landscape

It is just over 5 years sinceClinical and Experimental Immunology came under the direction of a new team of Editors and made a concerted effort to refresh its approach to promoting clinical and applied immunology through its pages. There were two major objectives: to foster papers in a field which, at the time, we loosely termed ‘translational immunology’; and to create a forum for the presentation and discussion of immunology that is relevant to clinicians operating in this space. So, how are we doing with these endeavours? This brief paper aims to summarize some of the key learning points and successes and highlight areas in which translational gaps remain.

Serologic evidence that ascaris and toxoplasma infections impact inflammatory responses to Helicobacter pylori in Colombians

BACKGROUND

Helicobacter pylori-infected children from coastal Tumaco, Colombia, have more parasitism, and adults have lower gastric cancer risk compared with high-altitude Pasto/Tuquerres residents. Because helminth and Toxoplasma gondii infections alter helicobacter gastritis in rodent models, we determined whether seropositivity to Ascaris lumbricoides or T. gondii was associated with Th2-IgG1 or Th1-IgG2 responses to H. pylori.

METHODS

Sera (240) from the two populations were evaluated for A. lumbricoides and T. gondii seropositivity and results correlated with IgE and IgG isotype responses to H. pylori.

RESULTS

Most Tumaco children and adults were seropositive for A. lumbricoides (89%, 66%), T. gondii (59%, 98%), or both (45%, 66%). In contrast, seropositivity among Pasto/Tuquerres children was much lower (9%A. lumbricoides, 11%T. gondii, and 2% dual positive) but increased in adults (58%A. lumbricoides, 82%T. gondii, and 41% dual positive). A. lumbricoides seropositivity correlated with elevated IgE and anti-inflammatory Th2-IgG1 responses to H. pylori, while T. gondiigondii seropositivity was linked to elevated IgE, pro-inflammatory Th1-IgG2, IgG3, and IgG4 responses to H. pylori. Individuals with high T. gondii titers had reduced Th1-IgG2, IgG3, and IgG4 responses to H. pylori.

CONCLUSIONS

Results support regional differences for childhood parasitism and indicate A. lumbricoides and T. gondii infections may impact inflammatory responses to H. pylori and partially explain differences in gastric cancer risk in Colombia.

99th Dahlem conference on infection, inflammation and chronic inflammatory disorders: lifestyle changes affecting the host-environment interface

In industrialized nations and high-income regions of the world, the decline of infectious diseases is paralleled by an increase in allergic, autoimmune and chronic inflammatory diseases (AACID). Changes in lifestyle in westernized societies, which impact individually and collectively on intestinal microbiota, may – at least in part – account for the AACID pandemic. Many disease genes that contribute to AACID encode pattern recognition and signalling molecules in barrier-associated cells. Interactions between gene products and environmental factors depend highly upon the host's state of maturation, the composition of the skin and gut microflora, and exposure to pollutants, antibiotics and nutrients. Inflammatory stress responses, if regulated appropriately, ensure immunity, health and relative longevity; when they are dysregulated, they can no longer be terminated appropriately and thus precipitate AACID. The 99th Dahlem Conference brought together experts of various disciplines (genetics, evolution biology, molecular biology, structural biology, cell biology, immunology, microbiology, nutrition science, epidemiology and clinical medicine) to discuss the multi-faceted relationships between infection, immunity and inflammation in barrier organs and the development of AACID. In Clinical and Experimental Immunology we are presenting a compilation of background papers that formed the basis of discussions. Controversial viewpoints and gaps in current knowledge were examined and new concepts for prevention and treatment of CID were formulated.

99th Dahlem conference on infection, inflammation and chronic inflammatory disorders: darwinian medicine and the 'hygiene' or 'old friends' hypothesis

The current synthesis of the 'hygiene hypothesis' suggests that the recent increase in chronic inflammatory disorders is at least partly attributable to immunodysregulation resulting from lack of exposure to microorganisms that have evolved an essential role in the establishment of the immune system. This document provides a background for discussion of the following propositions. 1. The essential role of these organisms is an example of 'evolved dependence'. 2. The most relevant organisms are those that co-evolved with mammals, and already accompanied early hominids in the Paleolithic. 3. More recently evolved 'childhood infections' are not likely to have evolved this role, and recent epidemiology supports this contention. 4. This mechanism is interacting with other modern environmental changes that also lead to enhanced inflammatory responses [inappropriate diet, obesity, psychological stress, vitamin D deficiency, pollution (dioxins), etc.]. 5. The range of chronic inflammatory disorders that is affected is potentially larger than usually assumed [allergies, autoimmunity, inflammatory bowel disease, but also vascular disease, some cancers, depression/anxiety (when accompanied by raised inflammatory cytokines), and perhaps neurodegenerative disorders and type 2 diabetes].