The role of dendritic cells in the immune niche of the peritoneum.

Dendritic cells (DCs) are professional antigen presenting cells that play an important role in the induction of T cell responses. Different subsets (cDC1s, cDC2s, pDCs, and moDCs) were described based on the expression of different surface markers and functions. In the context of peritoneum, DCs are also a key population cell orchestrating immune responses against pathogens, malignant cells and tissue-damage.

Optimising the IgG-degrading enzyme treatment regimen for enhanced adeno-associated virus transduction in the presence of neutralising antibodies.

Objective: Pre-existing neutralising antibodies (NAbs) to adeno-associated viruses (AAVs) remain an impediment for systemically administered AAV-mediated gene therapy treatment in many patients, and various strategies are under investigation to overcome this limitation. Here, IgG-degrading enzymes (Ides) derived from bacteria of the genus were tested for their ability to cleave human IgG and allow AAV-mediated transduction in individuals with pre-existing NAbs.

Methods: Cleavage activity of three different Ides was evaluated in serum from different species.

Epitope spreading driven by the joint action of CART cells and pharmacological STING stimulation counteracts tumor escape via antigen-loss variants.

Background: Target antigen (Ag) loss has emerged as a major cause of relapse after chimeric antigen receptor T (CART)-cell therapy. We reasoned that the combination of CART cells, with the consequent tumor debulking and release of Ags, together with an immunomodulatory agent, such as the stimulator of interferon gene ligand (STING-L) 2'3'-cyclic GMP-AMP (2'3'-cGAMP), may facilitate the activation of an endogenous response to secondary tumor Ags able to counteract this tumor escape mechanism.

Methods: Mice bearing B16-derived tumors expressing prostate-specific membrane Ag or gp75 were treated systemically with cognate CART cells followed by intratumoral injections of 2'3'-cGAMP.

AdrA as a Potential Immunomodulatory Candidate for STING-Mediated Antiviral Therapy That Required Both Type I IFN and TNF-α Production.

Several dinucleotide cyclases, including cyclic GMP-AMP synthase, and their involvement in STING-mediated immunity have been extensively studied. In this study, we tested five bacterial diguanylate cyclases from the Gram-negative bacterium Enteritidis, identifying AdrA as the most potent inducer of a STING-mediated IFN response. AdrA wild-type (wt) or its inactive version AdrA mutant (mut) were delivered by an adenovirus (Ad) vector.

TNF-alpha inhibition ameliorates HDV-induced liver damage in a mouse model of acute severe infection.

Background & Aims: HDV infection induces the most severe form of human viral hepatitis. However, the specific reasons for the severity of the disease remain unknown. Recently, we developed an HDV replication mouse model in which, for the first time, liver damage was detected.

Chemical modification of the adeno-associated virus capsid to improve gene delivery.

Gene delivery vectors based on adeno-associated virus (AAV) are highly promising due to several desirable features of this parent virus, including a lack of pathogenicity, efficient infection of dividing and non-dividing cells and sustained maintenance of the viral genome. However, the conclusion from clinical data using these vectors is that there is a need to develop new AAVs with a higher transduction efficiency and specificity for relevant target tissues. To overcome these limitations, we chemically modified the surface of the capsid of AAV vectors.

Genetic-Based Approaches to Inherited Metabolic Liver Diseases.

In vertebrates, the liver is the central metabolic organ of the body, which carries out an estimated 500 functions that range from general detoxification to protein synthesis, bile production, metabolism of fats, carbohydrates, proteins, bilirubin, vitamin and mineral storage and it even has an immune function. Hepatocytes are considered the professional liver cells, which carry out all of these functions. With such a variety of tasks to perform, it is not surprising that more than 400 rare monogenic disorders of hepatic origin have been described.

Evaluating antibody functional activity and strain-specificity of vaccine candidates for malaria in pregnancy using in vitro phagocytosis assays.

Background: Malaria in pregnancy is a major cause of poor maternal and infant health, and is associated with the sequestration of P. falciparum-infected erythrocytes (IE) in the placenta. The leading vaccine candidate for pregnancy malaria, VAR2CSA, has been shown to induce antibodies that inhibit IE adhesion to the placental receptor chondroitin sulfate A (CSA), potentially preventing placental infection.

Improvement of Adeno-Associated Virus-Mediated Liver Transduction Efficacy by Regional Administration in Macaca fascicularis.

The liver is a central organ in metabolism and can be affected by numerous inherited metabolic disorders. Recombinant adeno-associated virus (AAV)-based gene therapy represents a promising therapeutic approach for such diseases. AAVs have been demonstrated to be safe, and resulted in high and long-term expression in preclinical and clinical studies.

Adeno-Associated Viral Vectors Serotype 8 for Cell-Specific Delivery of Therapeutic Genes in the Central Nervous System.

Adeno-associated viruses (AAVs) have become highly promising tools for research and clinical applications in the central nervous system (CNS). However, specific delivery of genes to the cell type of interest is essential for the success of gene therapy and therefore a correct selection of the promoter plays a very important role. Here, AAV8 vectors carrying enhanced green fluorescent protein (eGFP) as reporter gene under the transcriptional control of different CNS-specific promoters were used and compared with a strong ubiquitous promoter.

Complementary Effects of Interleukin-15 and Alpha Interferon Induce Immunity in Hepatitis B Virus Transgenic Mice.

Unlabelled: In chronic hepatitis B (CHB), failure to control hepatitis B virus (HBV) is associated with T cell dysfunction. HBV transgenic mice mirror many features of the human disease, including T cell unresponsiveness, and thus represent an appropriate model in which to test novel therapeutic strategies. To date, the tolerant state of CD8(+) T cells in these animals could be altered only by strong immunogens or by immunization with HBV antigen-pulsed dendritic cells; however, the effectors induced were unable to suppress viral gene expression or replication.

New insights into acquisition, boosting, and longevity of immunity to malaria in pregnant women.

Background: How antimalarial antibodies are acquired and maintained during pregnancy and boosted after reinfection with Plasmodium falciparum and Plasmodium vivax is unknown.

Methods: A nested case-control study of 467 pregnant women (136 Plasmodium-infected cases and 331 uninfected control subjects) in northwestern Thailand was conducted. Antibody levels to P.

Differentiation of inflammatory dendritic cells is mediated by NF-κB1-dependent GM-CSF production in CD4 T cells.

Rel/NF-κB transcription factors regulate inflammatory and immune responses. Despite possible subunit redundancy, NF-κB1-deficient (Nfkb1(-/-)) mice were profoundly protected from sterile CD4 T cell-dependent acute inflammatory arthritis and peritonitis. We evaluated CD4 T cell function in Nfkb1(-/-) mice and found increased apoptosis and selectively reduced GM-CSF production.

Antibodies to a full-length VAR2CSA immunogen are broadly strain-transcendent but do not cross-inhibit different placental-type parasite isolates.

The high molecular weight, multidomain VAR2CSA protein mediating adhesion of Plasmodium falciparum-infected erythrocytes in the placenta is the leading candidate for a pregnancy malaria vaccine. However, it has been difficult so far to generate strong and consistent adhesion blocking antibody responses against most single-domain VAR2CSA immunogens. Recent advances in expression of the full-length recombinant protein showed it binds with much greater specificity and affinity to chondroitin sulphate A (CSA) than individual VAR2CSA domains.

Immunization with VAR2CSA-DBL5 recombinant protein elicits broadly cross-reactive antibodies to placental Plasmodium falciparum-infected erythrocytes.

Pregnancy-associated malaria is a severe clinical syndrome associated with the sequestration of Plasmodium falciparum-infected erythrocytes in the placenta. Placental binding is mediated by VAR2CSA, a member of the large and diverse P. falciparum erythrocyte membrane 1 (PfEMP1) protein family.

Evaluation of the antigenic diversity of placenta-binding Plasmodium falciparum variants and the antibody repertoire among pregnant women.

Pregnant women are infected by specific variants of Plasmodium falciparum that adhere and accumulate in the placenta. Using serological and molecular approaches, we assessed the global antigenic diversity of surface antigens expressed by placenta-binding isolates to better understand immunity to malaria in pregnancy and evolution of polymorphisms and to inform vaccine development. We found that placenta-binding isolates originating from all major regions where malaria occurs were commonly recognized by antibodies in different populations of pregnant women.

Sir2 paralogues cooperate to regulate virulence genes and antigenic variation in Plasmodium falciparum.

Cytoadherance of Plasmodium falciparum-infected erythrocytes in the brain, organs and peripheral microvasculature is linked to morbidity and mortality associated with severe malaria. Parasite-derived P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) molecules displayed on the erythrocyte surface are responsible for cytoadherance and undergo antigenic variation in the course of an infection.

Analysis of structure and function of the giant protein Pf332 in Plasmodium falciparum.

Virulence of Plasmodium falciparum, the most lethal parasitic disease in humans, results in part from adhesiveness and increased rigidity of infected erythrocytes. Pf332 is trafficked to the parasite-infected erythrocyte via Maurer's clefts, structures for protein sorting and export in the host erythrocyte. This protein has a domain similar to the Duffy-binding-like (DBL) domain, which functions by binding to receptors for adherence and invasion.

Measuring lymphocyte proliferation, survival and differentiation using CFSE time-series data.

Cellular proliferation is an essential feature of the adaptive immune response. The introduction of the division tracking dye carboxyfluorescein diacetate succinimidyl ester (CFSE) has made it possible to monitor the number of cell divisions during proliferation and to examine the relationship between proliferation and differentiation. Although qualitative examination of CFSE data may be useful, substantially more information about division and death rates can be extracted from quantitative CFSE time-series experiments.

TCR affinity promotes CD8+ T cell expansion by regulating survival.

Ligation with high affinity ligands are known to induce T lymphocytes to become fully activated effector cells while ligation with low affinity ligands (or partial agonists) may result in a delayed or incomplete response. We have examined the quantitative features of CD8(+) T cell proliferation induced by peptides of different TCR affinities at a range of concentrations in the mouse OT-I model. Both the frequency of cells responding and the average time taken for cells to reach their first division are affected by peptide concentration and affinity.

Transcriptional repressor Blimp-1 is essential for T cell homeostasis and self-tolerance.

T cell homeostasis is crucial for a functional immune system, as the accumulation of T cells resulting from lack of regulatory T cells or an inability to shut down immune responses can lead to inflammation and autoimmune pathology. Here we show that Blimp-1, a transcriptional repressor that is a 'master regulator' of terminal B cell differentiation, was expressed in a subset of antigen-experienced CD4(+) and CD8(+) T cells. Mice reconstituted with fetal liver stem cells expressing a mutant Blimp-1 lacking the DNA-binding domain developed a lethal multiorgan inflammatory disease caused by an accumulation of effector and memory T cells.

Bone marrow microenvironment facilitating dendritic cell: CD4 T cell interactions and maintenance of CD4 memory.

This study shows that bone marrow (BM) stroma expresses constitutively multiple adhesion molecules (ICAM-1, VCAM-1, MadCAM-1, P-selectin) relevant for the homing and infiltration of BM by blood derived T lymphocytes, and also the co-stimulatory molecule CD80, relevant for T cell activation. T cells were capable of homing to BM but not to thymus. Homing to BM involved the integrins LFA-1alpha and alpha4 which interact with the above constitutively expressed cell adhesion molecules (CAMs).