Avaliação da associação de um peptídeo imunogênico da proteína apolipoproteína n-acetiltransferase de Brucella abortus com nanopartículas de ouro sobre macrófagos : Efeito adjuvante de nanopartículas de ouro com peptídeo de Brucella abortus em macrófagos

Abstract

Bacteria of the genus Brucella, a gram-negative cocobacil, are classified based on their primary hosts, with Brucella Abortus as the most distributed globally and mainly affecting the cattle population, causing abortion and infertility. Currently the form of control of this disease is the vaccination of the animals, but vaccines that are marketed use attenuated strains, and although immunogenic, have various disadvantages, such as the prevalence of seropositive tests in cattle, occurring incidence of virulence and accidental contamination. Because of this, subunit vaccines are promising, safe, effective and lower cost for production. From this perspective, the present work aims to evaluate the conjugation of B. Abortus strain 2308 immunogenic peptide "AIPYILESTPQALAH” with AuNPs and characterize this association on macrophages. AuNPs were synthesized, followed by immobilization with 11-mercaptoundecanoic acid (MUA) and functionalization with the chemical reaction of 1-ethyl-3-(3- dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinamide (NHS). Each step of the synthesis was evaluated and the components characterized by FTIR, SEM-FEG, UV/VIS and DLS. The data indicate success in the association of AuNPs@MUA and the peptide. In order to understand the influence of the bioconjugate, murine bone marrow-derived macrophages (BMDM) were obtained and treated. The MTT test showed a decrease in cell viability of approximately 40% in the samples with AuNPs regardless of the bioconjugation, showing a certain degree of toxicity of AuNPs. However, AuNPs were able to promote an increase in the metabolic activity of macrophages, with glucose consumption and increased lactate production. There was also secretion of pro-inflammatory cytokines IL-6 and TNF-α, followed by nitric oxide production, indicating that the nanoparticle is already capable of generating an adjuvant effect, while the bioconjugate presented the same responses, but in a less elevated manner, indicating good biocompatibility. The results indicate a promising bioconjugate to be evaluated in preclinical models for a greater scope of the therapeutic and immunological potential of this vaccine candidate in the future.