Designing a therapeutic hepatitis B vaccine to circumvent immune tolerance.

An effective prophylactic hepatitis B virus (HBV) vaccine has long been available but is ineffective for chronic infection. The primary cause of chronic hepatitis B (CHB) and greatest impediment for a therapeutic vaccine is the direct and indirect effects of immune tolerance to HBV antigens. The resulting defective CD4+/CD8+ T cell response, poor cytokine production, insufficient neutralizing antibody (nAb) and poor response to HBsAg vaccination characterize CHB infection. The objective of this study was to develop virus-like-particles (VLPs) that elicit nAb to prevent viral spread and prime CD4+/CD8+ T cells to eradicate intracellular HBV. Eight neutralizing B cell epitopes from the envelope PreS1 region were consolidated onto a species-variant of the HBV core protein, the woodchuck hepatitis core antigen (WHcAg). PreS1-specific B cell epitopes were chosen because of preferential expression on HBV virions. Because WHcAg and HBcAg are not crossreactive at the B cell level and only partially cross-reactive at the CD4+/CD8+ T cell level, CD4+ T cells specific for WHcAg-unique T cell sites can provide cognate T-B cell help for anti-PreS1 Ab production that is not curtailed by immune tolerance. Immunization of immune tolerant HBV transgenic (Tg) mice with PreS1-WHc VLPs elicited levels of high titer anti-PreS1 nAbs equivalent to wildtype mice. Passive transfer of PreS1 nAbs into human-liver chimeric mice prevented acute infection and cleared serum HBV from mice previously infected with HBV in a model of CHB. At the T cell level, PreS1-WHc VLPs and hybrid WHcAg/HBcAg DNA immunogens elicited HBcAg-specific CD4+ Th and CD8+ CTL responses.

[2008 update of the 8th Consensus Development Conference of the Francophone Society of Medical Emergencies of 1999. The treatment of adult renal colic by the emergency services and in emergency rooms]. / Actualisation 2008 de la 8e Conférence de consensus de la Société francophone d'urgences médicales de 1999. Prise en charge des coliques néphrétiques de l'adulte dans les services d'accueil et d'urgences.

The care in the emergencies of the renal colic at the adult was the object in 1999 of a conference of consensus of the French Society of Emergency (SFMU) in association with the French Association of Urology and the Society of Nephrology. This already former text was the object of an update in 2008 by the subcommittee of scientific monitoring of the SFMU and was presented to the congress 2008. This public presentation in the presence of an expert urologist allowed to confront this new text with the practices and to publish an updating of the conference of consensus of 1999. A survey of practice was led with the emergency physicians, whose results are presented.

[Assisted reproduction project: legal constraints, ethical considerations]. / Projet parental: contraintes légales, considérations éthiques.

The ART law on that governs the IVF assisted reproduction project in many ways seems more or less contestable from an ethical point of view, even casting doubt on the justice of the legislative measures in the hope that ethical reflection would be pursued at the institutional level as well as in clinical ethical centers, so that more human solutions can be found.

The role of the HBV envelope proteins in the HDV replication cycle.

The hepatitis delta virus (HDV) is a subviral agent that utilizes the envelope proteins of the hepatitis B virus (HBV) for propagation. When introduced into permissive cells, the HDV RNA genome replicates and associates with multiple copies of the HDV-encoded proteins to assemble a ribonucleoprotein (RNP) complex. The mechanism necessary to export the RNP from the cell is provided by the HBV envelope proteins, which have the capacity to assemble lipoprotein vesicles that bud into the lumen of a pre-Golgi compartment before being secreted. In addition to allowing the release of the HDV RNP, the HBV envelope proteins also provide a means for its targeting to an uninfected cell, thereby ensuring the spread of HDV. This chapter covers the molecular aspects of the HBV envelope protein functions in the HDV replication cycle, in particular the activity of the small envelope protein in RNP export and the function of the large envelope protein at viral entry.

Taskforce 8: ethics of medically assisted fertility treatment for HIV positive men and women.

In this 8th statement of the ESHRE Taskforce on Ethics and Law, the focus is on the ethical issues raised by (assisted) reproduction for HIV positive men and women. Due to treatment improvements, their life expectancy has increased substantially. This, in combination with the reduction of perinatal transmission to the child, makes the creation of a family more acceptable. Recommendations are made concerning methods of avoiding HIV transmission in the couple and to their offspring. It is concluded that, if certain precautions are taken, medical assistance to reproduction of HIV positive people is ethically acceptable. For the time being, only cases of serodiscordant couples should be considered.

Taskforce 5: preimplantation genetic diagnosis.

The European Society of Human Reproduction and Embryology (ESHRE) Ethics Task Force sets out a recommended multidisciplinary approach to the application of preimplantation genetic diagnosis (PGD). The statement includes consideration of fundamental ethical principles, specific problems in cases of high genetic risk, and PGD for aneuploidy screening, HLA typing and sex selection for non-medical reasons.

[The right to be aborted]. / Le droit de ne pas naître.

This lecture deals with the difficult problem of so called "wrongful life". Two Court decisions have been issued recently in France and lead to a very ambiguous situation since they differ dramatically. In the "Perruche affair" where a diagnosis of rubella was not done, the parents prevented to get an interruption of pregnancy, and the child severely affected, the Court (Cour de Cassation, i.e. Supreme Court in charge of civil affairs) decided to compensate the child for "not having be aborted". In the "Quarez affair" where a diagnosis of Down syndrome was not done, the parents prevented to get an interruption of pregnancy, the Court (Conseil d'Etat, i.e. Supreme Court in charge of "administrative" affairs, affairs opposing individuals to state administration since the hospital in cause was belonging to the public sector) decided not to compensate directly the affected child. The consequences of these opposite decisions are analysed according to medical, legal, ethical and economic considerations.

[Informed consent and principle of precaution]. / Droit à l'information et principe de précaution.

The so called principle of precaution can be applied to the medical activity according to two opposite conceptions : in a traditional way, the practitioner is acting following the line he/she presumes to be in the best interests of the patient, despite the psychological burden of this attitude. The information given to the patient is modulated accordingly. Such attitude is nowadays considered as excessively paternalistic. Following the recent Court decisions the information must now become absolutely complete, including the very serious, albeit exceptional, consequences of the treatments, in order to allow the patient to make in every circumstance an informed choice. Such an attitude leads to a very efficient protection of the practitioner. However, the consequences may be detrimental for the individual patients, as well as for the whole society.

Mutations in the carboxyl-terminal domain of the small hepatitis B virus envelope protein impair the assembly of hepatitis delta virus particles.

The carboxyl-terminal domain of the small (S) envelope protein of hepatitis B virus was subjected to mutagenesis to identify sequences important for the envelopment of the nucleocapsid during morphogenesis of hepatitis delta virus (HDV) virions. The mutations consisted of carboxyl-terminal truncations of 4 to 64 amino acid residues and small combined deletions and insertions spanning the entire hydrophobic domain between residues 163 and 224. Truncation of as few as 14 residues partially inhibited glycosylation and secretion of S and prevented assembly or stability of HDV virions. Short internal combined deletions and insertions were tolerated for secretion of subviral particles with the exceptions of those affecting residues 164 to 173 and 219 to 223. However, mutants competent for subviral particle secretion had a reduced capacity for HDV assembly compared to that of the wild type. One exception was a mutant carrying a deletion of residues 214 to 218, which exhibited a twofold increase in HDV assembly (or stability), whereas deletions of residues 179 to 183, 194 to 198, and 199 to 203 were the most inhibitory. Substitutions of single amino acids between residues 194 and 198 demonstrated that HDV assembly deficiency could be assigned to the replacement of the tryptophan residue at position 196. We concluded that assembly of stable HDV particles requires a specific function of the carboxyl terminus of S which is mediated at least in part by Trp-196.

Effect of mutations in the small envelope protein of hepatitis B virus on assembly and secretion of hepatitis delta virus.

The gene coding for the small (S) envelope protein of hepatitis B virus was mutated to identify sequences important for the envelopment of the nucleocapsid during morphogenesis of hepatitis delta virus (HDV) virions. This study was focused on a domain of the S protein that is exposed in the cytoplasm during synthesis and thereby represented a good candidate for interaction with the viral nucleocapsid during virion assembly. The mutations consisted of deletion/insertions spanning the entire cytosolic domain of S between amino acid residues 24 and 80. Although the expression of mutants clustered between residues 59 and 80 could not be obtained, we demonstrated that a large part of the cytosolic loop, from residues 29-47 and 49-59, does not contain motifs essential for production of hepatitis B virus subviral particles or HDV virions. However, deletion of residues 24-28 led to the synthesis of S protein mutant, which was competent for secretion of subviral particles but deficient for production of HDV. We concluded that the sequence between Arg-24 and Ile-28 located at the carboxyl boundary of the transmembrane signal I for S contains residue or residues important for HDV particle assembly.