RESUMEN
Extracellular heat shock proteins (HSPs) mediate immunological functions and are involved in pathologies such as infection, stress, and cancer. Here, we demonstrated the dependence of an amount of HSP70 and HSP90 in serum vs. severity of acute pancreatitis (AP) on a cohort of 49 patients. Tethered bilayer lipid membranes (tBLMs) have been developed to investigate HSPs' interactions with tBLMs that can be probed by electrochemical impedance spectroscopy (EIS). The results revealed that HSP70 and HSP90 interact via different mechanisms. HSP70 shows the damage of the membrane, while HSP90 increases the insulation properties of tBLM. These findings provide evidence that EIS offers a novel approach for the study of the changes in membrane integrity induced by HSPs proteins. Herein, we present an alternative electrochemical technique, without any immunoprobes, that allows for the monitoring of HSPs on nanoscaled tBLM arrangement in biologics samples such us human urine. This study demonstrates the great potential of tBLM to be used as a membrane based biosensor for novel, simple, and non-invasive label-free analytical system for the prediction of AP severity.
RESUMEN
BACKGROUND: The central molecule in the pathogenesis of Alzheimer's disease (AD) is believed to be a small-sized polypeptide - beta amyloid (Aß) which has an ability to assemble spontaneously into oligomers. Various studies concerning therapeutic and prophylactic approaches for AD are based on the immunotherapy using antibodies against Aß. It has been suggested that either active immunization with Aß or passive immunization with anti-Aß antibodies might help to prevent or reduce the symptoms of the disease. However, knowledge on the mechanisms of Aß-induced immune response is rather limited. Previous research on Aß1-42 oligomers in rat brain cultures showed that the neurotoxicity of these oligomers considerably depends on their size. In the current study, we evaluated the dependence of immunogenicity of Aß1-42 oligomers on the size of oligomeric particles and identified the immunodominant epitopes of the oligomers. RESULTS: Mice were immunized with various Aß1-42 oligomers. The analysis of serum antibodies revealed that small Aß1-42 oligomers (1-2 nm in size) are highly immunogenic. They induced predominantly IgG2b and IgG2a responses. In contrast, larger Aß1-42 oligomers and monomers induced weaker IgG response in immunized mice. The monoclonal antibody against 1-2 nm Aß1-42 oligomers was generated and used for antigenic characterization of Aß1-42 oligomers. Epitope mapping of both monoclonal and polyclonal antibodies demonstrated that the main immunodominant region of the 1-2 nm Aß1-42 oligomers is located at the amino-terminus (N-terminus) of the peptide, between amino acids 1 and 19. CONCLUSIONS: Small Aß1-42 oligomers of size 1-2 nm induce the strongest immune response in mice. The N-terminus of Aß1-42 oligomers represents an immunodominant region which indicates its surface localization and accessibility to the B cells. The results of the current study may be important for further development of Aß-based vaccination and immunotherapy strategies.