2'-Hydroxychalcones as an alternative treatment for trichomoniasis in association with metronidazole.

The treatment for trichomoniasis, based on 5'-nitroimidazol agents, has been presenting failures related to allergic reactions, side effects, and the emergence of resistant isolates. There are no alternative drugs approved for the treatment of these cases; thus, the search for new active molecules is necessary. In this scenario, chalcones have been extensively studied for their promising biological activities. Here, we presented the synthesis of three hydroxychalcones (3a, b, and c), in vitro and in silico analyses against Trichomonas vaginalis. The in vitro biological evaluation showed that hydroxychalcone 3c presented anti-T. vaginalis activity, with complete death in 12 h of incubation at minimum inhibitory concentration (MIC) of 100 µM. 3c showed a dose-dependent cytotoxicity against mammalian VERO cell line, but the association of 3c at 12.5 µM and metronidazole (MTZ) at 40 µM showed 95.31% activity against T. vaginalis trophozoites after 24 h of exposure and did not affect the VERO cell growth, appearing to be a good alternative. In silico analysis by molecular docking showed that 3c could inhibit the activity of TvMGL (methionine gamma-lyase), TvLDH (lactate dehydrogenase), and TvPNP (purine nucleoside phosphorylase) affecting the T. vaginalis survival and also suggesting a different mechanism of action from MTZ. Therefore, these results propose that hydroxychalcones are promising anti-T. vaginalis agents and must be considered for further investigations regarding trichomoniasis treatment.

Mycobacterium bovis BCG expressing the proteins CP40 or CP09720 of Corynebacterium pseudotuberculosis promotes protection in mice after challenge.

In this study, we assessed the survival and immune response of mice vaccinated with recombinant Mycobacterium bovis BCG Pasteur that expressed the CP40 or CP09720 proteins after the mice were challenged with a C. pseudotuberculosis MIC-6 virulent strain. Six groups of mice (n = 10 mice per group) were immunised with a sterile 0.9% saline solution (G1), 106 CFU of M. bovis BCG Pasteur (G2), 106 CFU of M. bovis BCG/cp40 (G3), 106 CFU of M. bovis BCG/cp09720 (G4), M. bovis BCG/cp40 boosted with rCP40 (G5), and M. bovis BCG/cp09720 boosted with rCP09720 (G6). The highest survival rate of 90% was observed in the G5 group, followed by 80% in the G6 group and 70% in the G3 and G4 groups. Moreover, a significantly greater induction of IFN-γ and IL-10 was found in the G3 group and higher IL-17 levels were recorded in the G5 group compared to their levels in the control group (G1) (p < 0.05). A specific humoral immune response (total IgG) was found in the G5 and G6 groups on day 42 compared to the level of response in the G1 group. These results indicated that the vector vaccine elicited significantly greater survival of mice in all experimental groups after a strong virulent challenge and induced a strong immune response.

NanH and PknG putative virulence factors as a recombinant subunit immunogen against Corynebacterium pseudotuberculosis infection in mice.

Despite the economic and zoonotic relevance of caseous lymphadenitis, a competent immunoprophylaxis tool is still necessary. Here, we evaluated two putative virulence factors of Corynebacterium pseudotuberculosis, rNanH, and rPknG, as recombinant subunit vaccines in a murine model against the infection by C. pseudotuberculosis. Three groups of ten Balb/c mice each were inoculated with a sterile 0.9% saline solution (G1), rNanH (G2), or rPknG (G3) in formulations containing saponin as an adjuvant. The mice received two vaccine doses intercalated by a 21-day interval and were challenged with 2 × 104 CFU/mL of the C. pseudotuberculosis MIC-6 strain 21 days after the last immunization. The total IgG, IgG1, and IgG2a production levels increased significantly in the experimental groups (G2 and G3) on day 42. The highest levels of IgG2a antibodies in G2 and G3 were observed compared to IgG1 levels. G3 showed a significant (p < 0.05) humoral response through higher production of total IgG at day 42 when compared to G2. A significant increase of mRNA expression levels of interleukin (IL)-17, tumor necrosis factor, and interferon-γ was observed only in G2, while IL-4 was significantly produced only by G3. The levels of IL-10 and IL-12 obtained were not significant in any group. The survival rates after the challenge were 20% for G3 and 60% for G2 (p < 0.05). Our findings suggest that the formulation containing rNanH and saponin (G2) resulted in the best protection against the challenge and was able to elicit a Th1 immune response in mice, and can be considered as a promising antigen in the development of an effective vaccine against caseous lymphadenitis.