Immunoinformatic approaches for ErpY-LemA chimeric protein design for use in leptospirosis control.

AIMS: Currently, immunoinformatic approaches have shown promise in rapidly and cost-effectively identifying new antigens from the Leptospira proteome. Chimeric multiepitope proteins offer a strategy with significant potential for implementation in diagnosis and vaccines development. METHODS AND RESULTS: In this study, we detail the immunoinformatic analyses and design of a new recombinant chimeric protein constructed with epitopes identified from the sequences of ErpY-like and LemA proteins, previously identified as potential antigens for controlling leptospirosis. We expressed the chimeric protein using Escherichia coli heterologous systems, evaluated its antigenicity using serum from naturally infected patients, and its immunogenicity in mice as an animal model, with Freund as an adjuvant. The resulting recombinant chimeric protein, named rErpY-LemA, was successfully expressed and purified using a prokaryotic system, with an expected mass of 35 kDa. Serologic assays using serum samples from naturally infected patients demonstrated recognition of the chimera protein by antibodies present in sera. Animals immunized with the chimera exhibited a significant IgG antibody response from the 7th day (P < 0.001), persisting until day 49 of experimentation, with a titer of 1:12,800 (P < 0.05). Notably, significant production of IgA, IgM, and IgG subclasses was observed in animals immunized with the chimera. CONCLUSIONS: These results highlight the promising role of immunoinformatics in rapidly identifying antigens and the potential of chimeric multiepitope proteins in developing effective strategies for leptospirosis control.

Antibodies anti-rFilF protein has anti-biofilm activity against carbapenem-resistant Acinetobacter baumannii.

Acinetobacter baumannii is an opportunistic bacterium that causes infection in several sites. Carbapenem-resistant A. baumannii strains (CRAb) lead the World Health Organization's list of 12 pathogens considered a priority for developing new antimicrobials. The pathogenicity of A. baumannii is related to the different virulence factors employed in the colonization of biotic and abiotic surfaces, biofilm formation and multidrug resistance. We analyze the outer membrane protein FilF from A. baumannii in silico and produce it in recombinant form (rFilF). rFilF protein was successfully expressed in Escherichia coli BL21 Star in an insoluble form. Immunization with rFilF induced significant anti-rFilF IgG antibody production in mice, detected by indirect enzyme-linked immunosorbent assay, since the first evaluation until 49th. On the last experimentation day, the predominant immunoglobulin found was IgG1 followed by IgG2a, IgG2b, IgM, IgG3, and IgA. We observe that interleukins 4 and 10 show significant production after the 28th day of experimentation in mice immunized with rFilF. Anti-rFilF pAbs were able to inhibit biofilm formation in nine CRAb strains evaluated, and in the standard strain ATCC® 19606. These results demonstrate the anti-biofilm activity of anti-rFilF antibodies, promising in the development of a non-antibiotic approach based on the control of CRAb strains.