Protein-peptide arrays for detection of specific anti-hepatitis D virus (HDV) genotype 1, 6, and 8 antibodies among HDV-infected patients by surface plasmon resonance imaging.

Liver diseases linked to hepatitis B-hepatitis D virus co- or superinfections are more severe than those during hepatitis B virus (HBV) monoinfection. The diagnosis of hepatitis D virus (HDV) infection therefore remains crucial in monitoring patients but is often overlooked. To integrate HDV markers into high-throughput viral hepatitis diagnostics, we studied the binding of anti-HDV antibodies (Abs) using surface plasmon resonance imaging (SPRi).

Relationship between humoral response against hepatitis C virus and disease overcome.

Abstract: Hepatitis C virus infection leads to liver disease whose severity can range from mild to serious lifelong illness. However the parameters involved in the evolution of the disease are still unknown. Among other factors, the virus-elicited antibody profile is suspected to play a role in the outcome of the disease.

Biosensor for direct cell detection, quantification and analysis.

Microarrays are promising tools for cell isolation and detection. However, they have yet to be widely applied in biology. This stems from a lack of demonstration of their sensitivity and compatibility with complex biological samples, and a lack of proof that their use does not induce aberrant cellular effects.

On chip real time monitoring of B-cells hybridoma secretion of immunoglobulin.

The secretions of molecules by cells are of tremendous interest for both fundamental insights studies and medical purposes. In this study, we propose a new biochip-based approach for the instantaneous monitoring of protein secretions, using antibody production by B lymphocytes cultured in vitro. This was possible thanks to the Surface Plasmon Resonance imaging (SPRi) of a protein biochip where antigen proteins (Hen Egg Lysozyme, HEL) were micro-arrayed along with series of control proteins.

Peptide-protein microarrays and surface plasmon resonance detection: biosensors for versatile biomolecular interaction analysis.

Biosensors in microarray format provide promising tools for high-throughput analyses of complex samples. Although they are able to detect, quantify and characterize a multitude of compounds, most of the available devices are specialized in the analysis of one type of interaction, limiting their application to a define area. The aim of our work was to develop and characterize versatile protein (or peptide) microarrays suitable for the simultaneous analysis of a large panel of biological interactions.

Analysis of the toxicity of gold nano particles on the immune system: effect on dendritic cell functions.

The effect of manufactured gold nanoparticles (NP) on the immune system was analysed through their ability to perturb the functions of dendritic cells (DC), a major actor of both innate and acquired immune responses. For this purpose, DCs were produced in culture from mouse bone marrow progenitors.The analysis of the viability of the cells after their incubation in the presence of gold NP shows that these NP are not cytotoxics even at high concentration.

Polypyrrole-peptide microarray for biomolecular interaction analysis by SPR imaging.

Nowadays, high-throughput analysis of biological events is a great challenge which could take benefit of the recent development of microarray devices. The great potential of such technology is related to the availability of a chip bearing a large set of probes, stable and easy to obtain, and suitable for ligand-binding detection. Here, we describe a new method based on polypyrrole chemistry, allowing the covalent immobilization of peptides in a microarray format and on a gold surface compatible with the use of surface plasmon resonance.

Human C3 deficiency associated with impairments in dendritic cell differentiation, memory B cells, and regulatory T cells.

Primary C3 deficiency, a rare autosomal inherited disease (OMIM 120700), was identified in a 2-year-old male suffering from recurrent pyogenic infections from early infancy with undetectable total complement hemolytic activity (CH50) and C3 values. The nonconsanguineous parents and the two patients' two siblings had 50% normal serum C3 concentration. The molecular abnormality associated a paternal allele coding C3 with the missense mutation p.

A new role for complement C3: regulation of antigen processing through an inhibitory activity.

Increasing evidence underlines the involvement of complement component C3 in the establishment of acquired immunity which appears to play a complex role and to act at different levels. As antigen proteolysis by antigen presenting cells is a key event in the control of antigen presentation efficiency, and consequently in the quality of the immune response, we investigated whether C3 could modulate this step. Our results demonstrate for the first time that C3 can interfere with antigen proteolysis: (i) proteolysis of tetanus toxin (TT) by the lysosomal fraction from a human monocytic cell line (U937) is impaired in the presence of C3, (ii) this effect is C3-specific and involves the C3c fragment of the protein, (iii) C3c is effective even after disulfide disruption, but none of its three constitutive peptides is individually accountable for this inhibitory effect and (iv) the target-protease(s) exhibit(s) a serine-protease activity.

Real-time detection of lymphocytes binding on an antibody chip using SPR imaging.

We demonstrate the use of SPR imaging for the detection of site-specific binding of either B or T lymphocyte populations on an electrochemically-grafted antibody array.

C3b complexation diversifies naturally processed T cell epitopes.

In addition to its well-established role in innate immunity, the complement component C3 is of critical importance in modulating the humoral response. In this study, we examined the effect of C3b linkage to tetanus toxin (TeNT) in the production of antigenic peptides inside human APC. We purified HLA-DR associated peptides isolated either from TeNT or TeNT-C3b pulsed cells.

Immunomodulatory properties of morbillivirus nucleoproteins.

Morbillivirus infections have been known for a long time to be associated with an acute immunosuppression in their natural hosts. Here, we show that recombinant Morbillivirus nucleoproteins from canine distemper virus, peste-des-petits-ruminants virus, and Rinderpest virus bind B-lymphocytes from dogs, goats, and cattle, respectively, similarly to measles virus nucleoprotein in humans. The use of surface plasmon resonance imaging allowed the real time detection of differential interactions between Morbillivirus nucleoproteins and FcgammaRIIb (CD32).

Clinically related protein-peptide interactions monitored in real time on novel peptide chips by surface plasmon resonance imaging.

Background: Developing rapid, high-throughput assays for detecting and characterizing protein-protein interactions is a great challenge in the postgenomic era. We have developed a new method that allows parallel analysis of multiple analytes in biological fluids and is suitable for biological and medical studies.

Methods: This technology for studying peptide-antibody interactions is based on polypyrrole-peptide chips and surface plasmon resonance imaging (SPRi).

Macrophages from C3-deficient mice have impaired potency to stimulate alloreactive T cells.

Impaired T-cell reactivity is a feature of C3-deficient mice in several disease models. The mechanism behind the reduced T-cell response is, however, poorly understood. We explored the hypothesis that antigen-presenting cells (APCs) from C3-/- mice have impaired potency to stimulate antigen-specific T cells, in an alloantigen-dependent model.

A polypyrrole protein microarray for antibody-antigen interaction studies using a label-free detection process.

Protein microarray is a promising technology that should combine rapidity and easy use with high throughput and versatility. This article describes a method in which an electrocopolymerization process is employed to graft biological molecules on to a chip so that surface plasmon resonance imaging may be used to detect molecular interactions. Copolymerization of pyrrole-modified protein and pyrrole is an efficient grafting process which immobilizes molecules at defined positions on a gold surface.

Complement receptors and B lymphocytes.

Most of the biological processes depend on cell-to-cell and protein-to-cell interactions, which take place through receptors present on the cell surface. Various physiological systems are linked by such interactions, as is the case for innate and adaptative immune response. There is increasing evidence that two of the main actors involved in host defense, namely, the proteins of the complement system (nonspecific response) and the B lymphocytes (specific response), are strongly connected through the complement receptors displayed on the B-cell surface.

Influence of complement C3 amount on IgG responses in early life: immunization with C3b-conjugated antigen increases murine neonatal antibody responses.

Complement component C3, which plays an important role in both the innate and adaptative immune response, is present at low level in human infants. We show here that: (i) serum C3 amount is weak also in infant mice, (ii) these young animals fail to upregulate C3 to adult levels following tetanus toxoid immunization, (iii) neonatal macrophages have a limited capacity to synthesize C3 upon LPS exposure, (iv) conjugation of antigen to C3b significantly enhances antibody response elicited in 1-week-old mice--although it does not increase primary IgG response in adult mice. Altogether, this identifies C3 as one of the factors limiting early life antibody response and emphasizes the potential interest of immunization strategies overcoming this limitation.

Improvement of long-lasting response and antibody affinity by the complexation of antigen with complement C3b.

Complement protein C3 plays a major role in cell regulation and immune response. This last point is mainly due to C3's capacity to act as a bifunctional link between antigen and immunocompetent cells. In a previous work, we have reported the adjuvant effect produced by linking C3 fragments to antigen.