A clinical trial project, coordinated by Inserm, involving the testing of a preventive vaccine against Ebola has been selected by the European Commission. The protocol plans to include participants throughout Europe and Africa to evaluate immune response and tolerance to a vaccine strategy named “prime boost”, based on the use of two candidate vaccines developed by Janssen, a pharmaceutical company of Johnson & Johnson.

© Fotolia

The development and rapid access to treatment and candidate vaccines are among the WHO’s recommendations to stop the transmission of the Ebola virus and prevent the international spread of infection. Since the beginning of the epidemic, the French and international scientific community has been actively working towards these objectives.

Inserm has established an academic partnership with the London School of Hygiene and Tropical Medicine (LSHTM), as well as an industrial partnership (Crucell Holland BV; one of Janssen’s companies), The University of Oxford and the Centre Muraz to develop a vaccination from Phase 1 to Phase 3 that combines two vaccines derived from viral vectors (Ad26.ZEBOV et MVA-BN-Filo[1]). This project has been selected for funding by the European Commission under the second call for IMI2 (Innovative Medicines Initiative) projects. As part of this programme, Inserm will conduct Phase 2 trials in Europe and Africa, coordinated by Prof. Rodolphe Thiébaut.

These Phase 2 trials will evaluate the tolerance and quality of the immune response to the vaccine strategy. These tests will supplement data from Phase 1 trials that are currently in progress in the United States, England and are soon to be conducted in Africa. The data will be available in March 2015 and will be critical to evaluating effectiveness in areas at risk.

“This strategy, unlike conventional immunization protocols that involve one or more administrations of the same vaccine, is based on the concept of a vaccination involving several steps with two different vectors that will expose the organism to the same antigens in several ways. This is a new approach in the development of a vaccine against Ebola” stated Prof. Yves Levy, Inserm CEO.

The Grant Agreement is currently being finalised. Definitive information on the project, including the budget, will be published once the agreement has been signed.

[1] Both viral vectors used are conventional vectors that are already widely used in humans in several vaccines for other infectious diseases.

The complete genomes of 16 anopheline mosquito species from the five continents have just been sequenced. Ten years of research have enabled an international consortium, coordinated by the University of Michigan and University of Notre Dame (United States) and including researchers from the French Institute for Development Research (IRD) and Inserm, to publish in the 27 November 2014 issue of the journal Science the DNA sequence for these mosquitoes, which are vectors of malaria. These results lead the way to the development of comparative genomic studies, and will make it possible to improve strategies for vector control, which are essential to controlling the disease in the absence of a vaccine.

© IRD/ M. Dukhan : female mosquito : Anopheles sundaicus

Malaria causes over 600,000 deaths a year, mainly in Sub-Saharan Africa. The parasites, from the genus Plasmodium, are transmitted by mosquitoes of the genus Anopheles. Of the 450 Anopheles species on the planet, only a dozen are responsible for most of the transmission to humans.

In order to improve vector control strategies, researchers have devoted many years to decoding the genome of Anopheles species. That of the African mosquito, Anopheles gambiae, a major vector of malaria, has been available since 2002. Those of its South American (Anopheles darlingi) and Indian (Anopheles stephensi) homologues have been the subject of recent publications, in 2013 and 2014 respectively. Until now, the lack of knowledge on the genetic resources of other Anopheles species has restricted comparisons that would enable the identification the key features determining the ability of some mosquitoes to transmit the parasites.

10 years of North/South partnership

Led by the University of Michigan’s Broad Institute and the University of Notre Dame’s Eck Institute, over a period of 10 years the international consortium enlisted over a hundred researchers from 50 research institutes from the northern (United States, Europe) and southern (Africa, Asia, South America, Oceania, Australia) hemispheres.

The researchers studied Anopheles specimens from many regions in the world: Africa, Asia, Asia Minor, Central America and Oceania. They combined the most recent techniques for sequencing, assembly of genomes and of expressed genes, and chromosome mapping, using innovative methodologies for sequence analysis and genome comparison. Using this multidisciplinary approach, the researchers succeeded in sequencing and annotating the complete genomes of 16 new Anopheles species.

Strong genetic evolution in Anopheles

The sequenced genomes turned out to be very different, both in their composition and their general organisation. Thus their size varies from 135 to 275 million base pairs. Between 10,000 and 16,000 genes were identified per species. The first comparative analyses showed strong genetic peculiarities, including a high rate of molecular evolution compared with other insects (particularly Drosophila), and substantial genomic plasticity, with much gain and loss of genes (or entire groups of genes) in the course of evolution.

Analyses carried out on certain groups of genes involved in key elements of anopheline biology—such as reproduction, immune system, insecticide resistance, composition of the cuticle or saliva, odour perception or hormonal communication—enabled the researchers to identify a certain number of specific genes and traits acquired during evolution, which underpin the emergence of anthropophily[1] and parasite transmission in anophelines.

The knowledge of this genetic material improves the understanding of the mechanisms by which the vectors adapt to humans and their environment. The researchers now have new avenues of research for making their vector control strategies more effective, and controlling the transmission of malaria.

[1] Describes organisms (plant or animal) that live in contact with humans or in places they frequent.

Erosive oral lichen planus (OLP) is an auto-immune disease affecting skin and mucous membranes which results in an abnormal immune response against mucocutaneous cells. Today, scientists at the Institut Pasteur, Inserm, Paul Sabatier University (Toulouse) and the CNRS have proven that the immune cells involved in OLP are the same as those activated during an immune response to human papillomavirus (type HPV-16). This suggests a link between OLP and HPV. The results of this study were published in the Journal of Investigative Dermatology.

Erosive oral lichen planus (OLP) is an inflammatory disease which is considered auto-immune because of the abnormal immune response it triggers against other cells in the body. The condition affects mucous membranes around the mouth and genitals causing lesions and the destruction of skin cells called keratinocytes. Because current treatments are only partially effective, the condition is chronic and, although rare (between 0.1 and 4% of the overall population is affected), OLP can have serious side effects such as pain, difficulty eating, and cancer.

Papillomavirus© Institut Pasteur

Little was known about the underlying biological mechanisms of OLP until teams led by Marie-Lise Gougeon (Institut Pasteur), Nicolas Fazilleau (Inserm, Paul Sabatier University, CNRS) and Hervé Bachelez (Sorbonne Paris Cité, Paris Diderot University) demonstrated that the immune response which leads to the destruction of mucosal cells involves the same lymphocytes responsible for the immune response to human papillomavirus (HPV). This would suggest a link between OLP and infection by the HPV-16 strain, a virus known to be responsible for genital warts and cervical cancer.

Initial analyses of lesional tissue and blood samples from OLP patients revealed the presence of cytotoxic lymphocytes around the destroyed cells. This prompted scientists to try to characterize the specific role and origin of these lymphocytes.

For the ten patients enrolled in a study by Manuelle Viguier (Institut Pasteur, Sorbonne Paris Cité, Paris Diderot University), analyses showed an abnormally high population of a particular type of lymphocyte specific for HPV-16: T CD8 (type Vβ3).

The proportion of this type of lymphocyte was then measured during the different phases of OLP (outbreaks or remission stages). This allowed the scientists to show that the number of these cells decreased during periods of clinical remission and multiplied during outbreaks.

One of the theories put forward by the scientists was that keratinocytes in OLP patients might express an autoantigen (an endogenous normal tissue constituent) very similar to the HPV-16 antigen. This could be a source of confusion for T lymphocytes which, having already been exposed to HPV, might mistake the surface antigen on keratinocytes of OLP patients for the HPV antigen and trigger a cytotoxic immune response against keratinocytes.

This research indicates that the auto-immune disease OLP could involve T CD8 lymphocytes specific to HPV-16. This is the first time a link has been established between infection by HPV-16 and an auto-immune disease.

These results open up new therapeutic possibilities for treating severe forms of OLP. The Institut Pasteur has filed to patent this research in hopes that use of the HPV vaccine will be expanded to include OLP.

This study was financed by the French Dermatological Society, the Fondation ARC (Cancer Research Foundation), the French Cancer League, the French National Cancer Institute, the Midi-Pyrénées Regional Council and the Marie Curie International Re-integration Grant.

The main cause of death in patients suffering from cystic fibrosis is respiratory infection caused by different bacterial populations, which vary according to the age of the patient. Scientists at the Institut Pasteur and Inserm have identified a novel mechanism used by the Pseudomonas aeruginosa bacterium to hijack the immune system of its host in order to eradicate another bacterium, Staphylococcus aureus (“golden staph”), and take its place in airways. These results were published in Nature Communications on October 7, 2014, and shed light on a phenomenon involved in the regulation of bacterial composition in the airways of patients suffering from cystic fibrosis. They could also have an impact on our understanding of how intestinal microbiota evolves.

Cystic fibrosis is the most common serious hereditary genetic disease in the Caucasian population, and is due to a mutation of the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) chloride channel.This mutation leads to a fatal impairment of the respiratory system, which affects one in 2,500 births in Europe and North America. Life expectancy of patients is about 30 to 40 years. CFTR mutation leads to the abundant secretion of a thick mucus by airways in the lungs, which promotes bacterial infection. These infections are treated with antibiotics and, over time, this leads to bacterial multiresistance. Bacterial infections in airways are the main cause of patient death.

In patients suffering from cystic fibrosis, bacterial populations in airways vary depending on the patient’s age. The team working under Lhousseine Touqui, a scientist in the Innate Host Defense and Inflammation Unit (Department of Infection and Epidemiology, Institut Pasteur / Inserm U874), looked at two bacteria commonly found in the airways of patients: a Gram positive bacterium, Staphylococcus aureus (“golden staph”), and a Gram negative bacterium, Pseudomonas aeruginosa. S. aureus is mainly present in the airways of young patients, and decreases with age until it becomes virtually absent at the end of life. P. aeruginosa, on the other hand, is practically absent in the airways of young patients, and then progressively increases over a lifetime, to be the most abundant bacterial type at the end of life. The scientists explained how this progressive shift of infection between the two bacteria takes place within patients’ airways over the course of a lifetime.

The scientists first of all proved that the predominance of P. aeruginosa at the end of life was not due solely to antibiotic resistance, since S. aureus presents the same resistance and nevertheless progressively disappears. They then showed that a particular enzyme produced by the airways of cystic fibrosis patients is instrumental in the elimination of S. aureus by P. aeruginosa. The latter uses the airway’s immune system to kill the S. aureus bacterium.

The Institut Pasteur and Inserm scientists have demonstrated the role played in this bacterial contest by an enzyme, type IIA phospholipase A2(sPLA2-IIA), whose ability to kill Gram positive bacteria such as S. aureus was already known. To date, sPLA2-IIA is known as the most powerful antimicrobial peptide produced by humans and able to kill S. aureus. The scientists noticed that, in animal models, P. aeruginosa stimulates the production of sPLA2-IIA in airways, which is then released by host cells and kills S. aureus.

In addition, it has emerged that sPLA2-IIA increases with patient age. This explains the fact that, with the appearance of P. aeruginosa at a certain age, secretion of sPLA2-IIA by the airways is triggered and kills S. aureus. It should also be noted that sPLA2-IIA is almost totally absent in the airways of healthy subjects. P. aeruginosa therefore manipulates its host in order to kill S. aureus, its bacterial competitor in the airways.

Scientists have therefore been able to explain a sophisticated and previously unknown mechanism implemented by a bacterium to manipulate its host and kill a competing bacterium. This discovery suggests that sPLA2-IIA probably plays a similar role in intestinal microbiota dynamics, as these microbiota populations also vary according to host age. Lastly, looking beyond cystic fibrosis patients, sPLA2-IIA could be injected into patients infected with Gram positive bacteria, which could be a useful alternative therapy to overcome bacterial resistance to antibiotics.

This study was supported by the French cystic fibrosis association Vaincre la Mucoviscidose, and the DIM Malinf research foundation (Greater Paris area).

Illustration: Pulmonary epithelium of patients suffering from cystic fibrosis

1. Stimulation of the production of sPLA2-IIA by Pseudomonas aeruginosa.
2. sPLA2-IIA kills Staphylococcus aureus.
   
   © Lhousseine Touqui, Institut Pasteur

A novel mode of defense against bacteria such as the causal agent of tuberculosis or Staphylococcus aureus has been identified in humans by studying a small, aquatic flatworm, the planarian. This discovery was made by scientists in the “Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes” (CNRS/IRD/Inserm/Aix-Marseille Université), working in collaboration with the “Centre Méditerranéen de Médecine Moléculaire” (Inserm/Université Nice Sophia Antipolis) and other national and international research groups (1). Their work, published in the journal Cell Host and Microbe on 10 September 2014, highlights the importance of studying alternative model organisms, and opens the way towards new treatments against bacterial infections.

© Eric Ghigo Dugesia japonica infected by green fluorescent Legionella pneumophila bacteria (located in the intestines of the worm).

By studying an original model organism, an aquatic flatworm called the planarian, scientists have succeeded in identifying a novel mode of defense against bacteria such as the causal agent of tuberculosis (Mycobacterium tuberculosis). Present in a latent state in humans, this mechanism could be stimulated by pharmacological intervention.

Scientists in the “Infection, Genre et Grossesse” (I2G) team led by Eric Ghigo had the idea of working on the planarian Dugesia japonica after observing that the discoveries made using classic immunological models (such as the Drosophila melanogaster fruit fly or the Caenorhabditis elegans roundworm) were dwindling. Previously, this flatworm was mainly known for its extraordinary regeneration capacities (2), which make it potentially immortal (it cannot die of old age). It is also able to resist bacteria that are highly pathogenic or even fatal in humans, as discovered by the research team — the only one in the world to have initiated immunological studies on this organism.

To understand the reasons for such an efficient immune defense mechanism, the scientists studied the genes expressed by the planarian following its infection by bacteria that are pathogenic in humans,such as M. tuberculosis, S. aureus and the causal agent of Legionnaires’ disease (Legionella pneumophila). They were thus able to identify 18 genes that make the flatworm resistant against these pathogens.

The scientists focused on one of these genes – MORN2 – which is present in the human genome and was found to be essential for eliminating all the bacteria tested. The team over-expressed this gene in human macrophages, the white blood cells responsible for eliminating pathogenic agents by digesting them (a process called phagocytosis). Thus stimulated, the macrophages became capable of eliminating the S. aureus, L. pneumophila and M. tuberculosis bacteria as well as many other pathogenic agents.

Detailed study of the mechanism of action of MORN2 revealed that it favors the sequestration (3) of M. tuberculosis in an intracellular cavity (the phagolysosome) where the bacterium is destroyed. In fact, the causal agent of tuberculosis usually succeeds in escaping this fate, so the bacterium can then remain in a latent state in the cells and reappear when the immune system becomes weakened. This discovery thus opens the way towards new opportunities in the fight against M. tuberculosis, antibiotic-resistant strains of which are becoming increasingly widespread.

This research also demonstrates the usefulness of “exotic” model organisms such as the planarian. Indeed, the MORN2 gene has been lost during the evolution of classic model organisms such as the D. melanogaster fruit fly, although it has been conserved in humans. Without the use of this new model, the mechanisms of the human immune response discovered during this study would have remained unknown.

This work benefited notably from CNRS support via a PEPS (Projet Exploratoire Premier Soutien) funding scheme designed to support exploratory research projects based on the creativity of research teams.

(1) in France, the Centre Commun de Microscopie Appliquée (Université Nice Sophia Antipolis); in Italy, the department of Clinical and and Experimental Medicine in Pisa; in New Zealand, the Otago Genomics and Bioinformatics Facility.

(2) In 1814, JG Dalyell discovered that a planarian cut into 279 fragments could regenerate itself in 15 days to produce 279 new worms.

(3) via a mechanism called “LC3-associated phagocytosis”.

Having proven effective in reducing the number of new HIV infections in men, circumcision also appears to play a role in the reduction of HIV incidence in women. These findings are from the study ANRS 12126 coordinated by Professor Bertran Auvert (Inserm U1018, Université de Versailles-Saint Quentin, Hôpital Ambroise Paré) and conducted in the township of Orange Farm in South Africa. They will be presented as an oral communication by Kévin Jean (Inserm U1018) at the 20th International AIDS Conference organized by the International AIDS Society and held at Melbourne from 20 to 25 July 2014

The World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS (UNAIDS) have, since 2007, recommended considering circumcision as a complementary strategy in the prevention of HIV infection in men. These recommendations are based on the study ANRS 12165, begun in 2002 in Orange Farm in South Africa by Professor Bertran Auvert (Inserm U1018, Université de Versailles-Saint Quentin, Hôpital Ambroise Paré), the results of which have been confirmed by two other trials conducted in Kenya and in Uganda. This strategy has been deployed principally in regions of South and East Africa where the rate of HIV infection by heterosexual transmission is high and the rate of circumcision is low.

In the framework of a previous study (ANRS 12126), Professor Bertran Auvert’s team has shown that circumcision seems to be well accepted by the male population when it is offered in real-life conditions. In Orange Farm, many men are willing to undergo circumcision (the rate of circumcision has increased from 12% to 53%) and the number of new infections in circumcised men has decreased (half as many new infections as in uncircumcised men). But what about women?

Kévin Jean and Bertran Auvert, together with their colleagues at the NICD/NHLS in Johannesburg, present, for the first time, on the occasion of the 20th International AIDS Conference of the International AIDS Society, the first data on the indirect effect of male circumcision on women.

In women who have intercourse only with circumcised men, circumcision appears to reduce the prevalence (proportion of people infected) and the incidence (rate of new infections) of HIV infection, and does not seem to promote risky behavior (increase in number of sexual partners, non-use of condoms).

The data are from the combination of three cross-sectional studies conducted in 2007, 2010 and 2012 among 2452 women aged 15 to 29. Blood test results, data on sexual behavior, and circumcision status of male sexual partners were recorded. First, the scientists compared the rate of HIV prevalence in women who only had circumcised sexual partners with the rate of HIV prevalence in women who had uncircumcised sexual partners. Over 30% of women reported having had sexual relations only with circumcised men. The rate of HIV prevalence in these women was 17.8%, whereas it was almost twice as high (30.4%) in women who had sexual relations with uncircumcised men.

Second, they used a mathematical model to estimate the HIV incidence rate in these two groups of women for the same period. The rate of new infections in women who only had circumcised sexual partners was 20% lower than in the other women.

These results confirm the importance of voluntary circumcision programs in national HIV/AIDS prevention programs.

The risk of transmission of HIV and of hepatitis C virus in intravenous drug users can be reduced significantly by means of support and educational sessions delivered by their peers.
This type of community intervention, which is easily transposable, has been evaluated in the framework of ANRS AERLI, a study conducted jointly by the nonprofit organizations AIDES, Médecins du Monde and by Inserm U912 (Marseille). The results were presented in an oral communication at the 20th International AIDS Conference organized by the International Aids Society and held in Melbourne (Australia) from 20 to 25 July 2014.

In all, 288 sessions were conducted among 113 drug users recruited in 8 centers specialized in offering help in risk reduction for drug users (CAARUD). A control group of 127 drug users, comparable in terms of drug injection history, age and sex, was set up in 9 other centers. All participants were questioned, at inclusion and again 6 and 12 months later, on injection behaviors involving a risk of transmission of hepatitis C virus and of complications at the injection site.

Data analysis revealed a significant benefit of the educational intervention. In the “Intervention” group, there was:

– a 43% decrease in injection practices involving a risk of transmission of hepatitis C virus (44% of drug users reported at least one unsafe practice before the intervention versus 25% 6 months later);

– a 41% decrease in complications at the injection site (66% of drug users reported complications before the intervention versus 39% 12 months later).

“In comparison with the control group, we observed a major effect of peer-to-peer education on practices that run the risk of infection transmission,” commented Patrizia Carrieri (Inserm U912). “This is all the more valuable as a large proportion of these drug users remain on the margins of the health care system.”

This type of intervention has two other advantages: it is inexpensive and is easily implemented in centers for drug users.

“This trial also demonstrates the relevance of community health care interventions, including in research, because the intervention model tested here derives directly from the peer support practices used by nonprofit organizations like AIDES and Médecins du Monde” emphasize Jean-Marie Le Gall, AIDES and Marie Debrus, Médecins du Monde.

“Given the observed benefits, said Professor Jean-François Delfraissy, ANRS (France REcherche Nord&sud Sida-hiv Hépatites) Director, it is now conceivable to set up the community intervention on a larger scale, thus enhancing risk reduction among drug users.

The first results of the pilot phase of the trial ANRS 12249 TasP show that the repeated offer of screening for HIV has been well accepted by a rural population in South Africa. The challenge remains of bringing infected individuals into health care facilities for treatment of the infection. These results were presented as an oral communication at the 20th International AIDS Conference organized by the International AIDS Society and held at Melbourne (Australia) from 20 to 25 July 2014.

Launched in March 2012, the ANRS 12249 TasP (Treatment as Prevention) Trial is one of four international randomized trials designed to assess the efficacy of the TasP strategy in a large population. It is conducted the province of KwaZulu-Natal, South Africa, one of the highest prevalence areas in the world, and the highest in South Africa (16.9% in 2012 according to the latest national survey of the general population).

In this trial, 22 geographical zones (“clusters”), each of approximately 1000 inhabitants, were defined and randomly divided into two groups (an intervention group and a control group comprising 11 clusters). All inhabitants were routinely offering repeated (every six months) rapid HIV testing in their homes. In the intervention group, people found to be seropositive were offered immediate antiretroviral treatment, whatever their CD4 cell count. In the comparison group, treatment was offered according to currently recommended South African Department of Health guidelines. Mobile clinics worked in each cluster to expedite access to care.

Results from the pilot phase of the trial, were presented at the international HIV meeting in Melbourne. This pilot phase was conducted in 10 geographic clusters containing over 12,000 residents above 16 years of age, and followed up for between 12 and 18 months. HIV status was determined in close to 9,000 of these individuals, either because they reported that they were seropositive or because they agreed to rapid HIV testing.

The initial findings are as follows:

HIV status was determined for 82% of those contacted, meaning that home-based testing was acceptable to this population. Among people who were found to be seronegative at the first home-based contact, 85% agreed to a second HIV test at the next home visit.

– Scientists also found a prevalence of HIV infection of 31%, much higher than the initial estimate.

– Around 25% of the 2,570 HIV infected individuals learned of their HIV status through the study.

– In respect to those diagnosed with HIV infected individuals and not already receiving therapy only 48% presented to a clinic within six months.  63% were linked within a year.

– In the intervention group, 80% of those with CD4 >350 cells/mm3 received therapy.

“These initial results are very important,” pointed out Professor François Dabis (Institut de Santé Publique, Epidémiologie et Développement, Inserm U 897, Bordeaux), one of the co-investigators of the trial, “because they validate the feasibility of the TasP strategy, which aims to test and treat the whole adult population so as to curb transmission.

“Validation of phase I of this trial is essential,” explained Professor Jean-François Delfraissy, Director of ANRS (France REcherche Nord&sud Sida-hiv Hépatites). “We can therefore pursue the trial.” The study entered its second phase in June 2014. The first results on the effect of TasP on the incidence of HIV infection in the population should be known by the end of 2016.