Generation of T-cell receptors targeting a genetically stable and immunodominant cytotoxic T-lymphocyte epitope within hepatitis C virus non-structural protein 3.

Hepatitis C virus (HCV) is a major cause of severe liver disease, and one major contributing factor is thought to involve a dysfunction of virus-specific T-cells. T-cell receptor (TCR) gene therapy with HCV-specific TCRs would increase the number of effector T-cells to promote virus clearance. We therefore took advantage of HLA-A2 transgenic mice to generate multiple TCR candidates against HCV using DNA vaccination followed by generation of stable T-cell-BW (T-BW) tumour hybrid cells.

Raltegravir treatment intensification does not alter cerebrospinal fluid HIV-1 infection or immunoactivation in subjects on suppressive therapy.

Background: Despite suppression of plasma human immunodeficiency virus type 1 (HIV-1) RNA by antiretroviral therapy to levels below clinical assay detection, infection and immune activation may persist within the central nervous system and possibly lead to continued brain injury. We hypothesized that intensifying therapy would decrease cerebrospinal fluid (CSF) infection and immune activation.

Methods: This was a 12-week, randomized, open-label pilot study comparing addition of the integrase inhibitor raltegravir to no treatment augmentation, with an option for rollover to raltegravir.

Amplified antigen-specific immune responses in HIV-1 infected individuals in a double blind DNA immunization and therapy interruption trial.

Immunotherapy in patients with HIV-1 infection aims to restore and broaden immunological competence, reduce viral load and thereby permit longer periods without combined antiretroviral treatment (cART). Twelve HIV-1-infected patients on cART were immunized on the skin with DNA plasmids containing genes of several HIV-1 subtypes with or without the addition of hydroxyurea (HU), or with placebo. The mean net gain of HIV-specific CD8+ T cell responses were higher and broader in the HIV DNA vaccine groups compared to non-vaccinated individuals (p<0.

Recombinant Modified Vaccinia Ankara (MVA) effectively boosts DNA-primed HIV-specific immune responses in humans despite pre-existing vaccinia immunity.

The presence of vector-specific immune responses may hamper the induction of responses to a foreign antigen encoded by the vector. We evaluated the impact of pre-existing immunity to vaccinia virus on the induction of HIV-specific responses after immunization of healthy volunteers with a HIV-1 DNA prime-MVA boost vaccine. Following three priming immunizations with HIV-1 DNA plasmids, the volunteers were boosted with a single injection of recombinant MVA encoding HIV-1 proteins.

Combining DNA technologies and different modes of immunization for induction of humoral and cellular anti-HIV-1 immune responses.

We show here that it is possible to combine two different genetic immunogens, one designed to induce HIV-1 specific humoral immune responses (pKCMVgp160B) and one designed to induce cellular anti-HIV-1 immune responses (Auxo-GTU-MultiHIV), and still retain the major properties of both vaccine constructs. The two different constructs were delivered using two different methods; the gene-gun and the Biojector, which both are needle-free devices. In BALB/c mice we were able to induce high levels of HIV-1-specific T cell responses as well as high levels of anti-gp160 antibodies by co-administrating the vaccine constructs.

SURFIN4.1, a schizont-merozoite associated protein in the SURFIN family of Plasmodium falciparum.

Background: In its effort to survive the human immune system, Plasmodium falciparum uses several parasite-derived antigens most of which are expressed at the surface of the parasitized red blood cells (pRBCs). Recently SURFINs, a new family of antigens encoded by the surf multi-gene family, has been reported. One member of the family, SURFIN4.

Intranasal immunization of young mice with a multigene HIV-1 vaccine in combination with the N3 adjuvant induces mucosal and systemic immune responses.

One of the major challenges for the development of an HIV vaccine is to induce potent virus-specific immune responses at the mucosal surfaces where transmission of virus occurs. Intranasal delivery of classical vaccines has been shown to induce good mucosal antibody responses, but so far for genetic vaccines the success has been limited. This study shows that young individuals are sensitive to nasal immunization with a genetic vaccine delivered in a formulation of a lipid adjuvant, the Eurocine N3.

Generation of cross-protective antibodies against Plasmodium falciparum sequestration by immunization with an erythrocyte membrane protein 1-duffy binding-like 1 alpha domain.

The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important virulence factor on the surface of infected erythrocytes. Naturally acquired antibodies to PfEMP1 expressed by parasites causing severe malaria are suggested to be protective and of major interest for the development of a vaccine against severe disease. In this study, the PfEMP1 expressed by a parasite clone displaying a multiadhesive phenotype associated with severe malaria was well recognized by sera of malaria semi-immune children.

Leishmanial amastigote antigen P-2 induces major histocompatibility complex class II-dependent natural killer-cell reactivity in cells from healthy donors.

Innate mechanisms involving natural killer cells have been implied to play an important role in immunity against Leishmania infection. Previous studies have evaluated responses to three purified amastigote antigens, P-2, P-4 and P-8, of Leishmania pifanoi. The P-4 and P-8 antigens have been demonstrated to induce protection in mouse models, as well as to induce cellular responses in American cutaneous leishmaniasis patients.

var genes, PfEMP1 and the human host.

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important virulence factor encoded by a family of roughly 60 var genes and is used by the parasite to interact with the human host. The parasite regularly exchanges the expressed var gene generating antigenic variation of the infected RBCs (pRBC) surface which is crucial for successful proliferation and transmission. PfEMP1 is also an adhesive molecule that binds to an array of human receptors.

Evaluation of amastigote reactive cells in human cutaneous leishmaniasis caused by Leishmania aethiopica.

Lymphoproliferative responses to three affinity chromatography purified amastigote antigens of Leishmania pifanoi, P-2, P-4 and P-8, were evaluated in peripheral blood mononuclear cells (PBMC) from patients with Ethiopian cutaneous leishmaniasis. Antigen-stimulated cells were analysed for the percentage of CD4+, CD8+ and CD16/56+ cells and the expressed levels of gamma interferon (IFNgamma) and interleukin (IL)-10 were determined in culture supernatants. The amastigote antigens induced cellular responses in leishmaniasis patients with heterologous Leishmania parasite infection.

Malaria pathogenesis: a jigsaw with an increasing number of pieces.

Plasmodium falciparum malaria remains as one of the most devastating global health problems of today. It is estimated that around 150 million individuals get the disease every year and of these 2-3 million die from it. Our knowledge of the mechanisms underlying the pathology has expanded greatly over the last decades, but many aspects of the molecular biology, immunology and epidemiology that govern the pathogenesis and spread of this parasite are still unclear.

Mosaic-like transcription of var genes in single Plasmodium falciparum parasites.

The var gene family of Plasmodium falciparum encodes the clonally variant adhesin PfEMP1 present on the surface of infected erythrocytes. A poorly understood mechanism of allelic exclusion controls the expression of PfEMP1. Transcription of var genes is developmentally and, most likely, epigenetically regulated.

Role of nonimmune IgG bound to PfEMP1 in placental malaria.

Infections with Plasmodium falciparum during pregnancy lead to the accumulation of parasitized red blood cells (infected erythrocytes, IEs) in the placenta. IEs of P. falciparum isolates that infect the human placenta were found to bind immunoglobulin G (IgG).

Binding of Plasmodium falciparum-infected erythrocytes to soluble platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31): frequent recognition by clinical isolates.

Platelet-endothelial cell adhesion molecule-1 or CD31 (PECAM-1/CD31) is a receptor recognized by Plasmodium falciparum-parasitized erythrocytes (pRBCs). Fluorescence-labeled soluble recombinant PECAM-1/CD31 (sPECAM-1/CD31) is shown to bind to the surface of P. falciparum-infected erythrocytes on up to 70% of the cells.

Induction and abrogation of LACK reactive cells in the evolution of human leishmaniasis.

Peripheral blood mononuclear cells (PBMC) from cutaneous leishmaniasis patients with ongoing Leishmania aethiopica infection and individuals cured/under treatment from L. infantum or L. donovani infection were stimulated in vitro with LACK, the Leishmania homologue of receptors for activated C kinase.

Differential induction of cellular responses by live and dead Leishmania promastigotes in healthy donors.

The most effective protection against human leishmaniasis has been achieved following vaccination with live promastigotes. Killed promastigotes + BCG can protect, albeit to a lower degree. To explore what mechanisms may be involved in these differences, the ability of live and dead promastigotes to induce immune responses were evaluated in vitro.

The duffy-binding-like domain 1 of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a heparan sulfate ligand that requires 12 mers for binding.

The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), present on the surfaces of parasitized red blood cells (pRBC), mediates rosetting, a virulent phenotype. Here, we show that pRBC specifically bind heparan sulfate (HS) and heparin onto their surfaces and that the rosetting ligand PfEMP1 specifically adheres to heparin-Sepharose when extracted from the surfaces of radioiodinated infected RBC. An analysis of the binding properties of the different regions of PfEMP1 provides evidence that the Duffy-binding-like domain-1 (DBL-1) is the predominant ligand involved in HS and heparin binding.

Indications of the protective role of natural killer cells in human cutaneous leishmaniasis in an area of endemicity.

The role of natural versus acquired immunity to Leishmania aethiopica infection in humans is the focus of our studies. We found in previous studies that mononuclear cells from nonexposed healthy Swedish donors responded to Leishmania antigen stimulation by proliferation and gamma interferon production. The main cell type responding was CD3- CD16/56+ natural killer (NK) cells.