Larvae of the black soldier fly, Hermetia illucens are well‐known fly larvae that inhabit many countries around the world. Antimicrobial agents derived from the larvae may be among the substances that are produced in the body for their survival. This study was carried out to identify the antimicrobial effects of H. illucens larvae that commonly inhabit animal waste and food waste. To evaluate the pharmacological effects of H. illucens larvae extracts, the larvae were extracted by various organic solvents, and their antibacterial effects were determined by antimicrobial methods, such as agar disk diffusion and turbidometric assays. The methanol extracts (ME) indicated antibacterial effects against the proliferation of Klebsiella pneumoniae, Neisseria gonorrhoeae and Shigella sonnei. However, antibacterial effects were not induced in Gram‐positive bacteria such as Bacillus subtilis, Streptococcus mutans and Sarcina lutea. The bacterial growth treated with ME was strongly inhibited from 20 mg/mL in a dose‐dependent manner compared with other extracts, and antibacterial activity gradually decreased after 24 h. Moreover, the minimal inhibitory concentration (MIC) values of ME against Klebsiella pneumoniae, Neisseria gonorrhoeae and Shigella sonnei for 12 h were measured as 44.74 mg/mL, 43.98 mg/mL and 43.96 mg/mL, respectively. These results demonstrate that ME of H. illucens larvae not only has antibacterial activity which strongly inhibits the growth and proliferation of the bacteria but also unique properties which effectively block the viability of the bacteria.

Rhoptry organelle proteins (ROPs) secreted by Toxoplasma gondii (T. gondii) play a critical role during parasite invasion into host cells. In this study, virus-like particles (VLPs) vaccines containing ROP4 and/or ROP13 together with influenza M1 were generated. ROP4+ROP13 VLPs were produced by combining ROP4 VLPs with ROP13 VLPs, and ROP(4 + 13) VLPs by co-infecting insect cells with recombinant baculovirus expressing ROP4 or ROP13. Mice intranasally immunized with ROP(4 + 13) VLPs showed significantly higher levels of IgG, IgG1, IgG2a and IgA antibody responses in sera compared to ROP4+ROP13VLPs. Upon challenge infection by oral route, mice immunized with ROP(4 + 13) VLPs elicited higher levels of IgG and IgA antibody responses in fecal, urine, intestine and vaginal samples as well as CD4+ T, CD8+ T cells, and germinal center B cell responses compared to other type of vaccines, ROP4 VLPs, ROP13 VLPs, and ROP4+ROP13 VLPs. ROP(4 + 13) VLPs vaccination showed a significant decrease in the size and number of cyst in the brain and less body weight loss compared to combination ROP4+ROP13 VLPs upon challenge infection with T. gondii ME49. These results indicated that the ROP(4 + 13) VLPs vaccination provided enhanced protection against T. gondii infection compared to ROP4+ROP13 VLPs, providing an important insight into vaccine design strategy for T. gondii VLPs vaccines.

Despite the ability to induce a broad range of cross protection, M2e5x virus-like particles (VLPs) alone provide limited vaccine efficacy and confer low efficacy of protection against highly pathogenic avian influenza virus (HPAIV) infection in chickens. Avian influenza hemagglutinin (HA) has been a major antigenic target that enhances humoral immunity, but the efficacy of avian HA-based vaccines against HPAIV needs to be further improved. In this study, we evaluated the vaccine efficacy induced by combination of conserved tandem repeat M2e5x VLPs and HA VLPs against an avian influenza virus. We found that combinatorial vaccine elicited higher levels of reassortant H5N1 (rgH5N1) virus-specific IgG, IgG1, IgG2a and IgA antibody responses compared to M2e5x VLPs in sera and lungs of mice. Combinatorial VLPs vaccination induced higher levels of CD8 + T cell and germinal center B cell responses in lung and spleen compared to M2e5x VLPs. Combinatorial VLPs vaccination showed significantly reduced inflammatory responses and lung viral loads upon rgH5N1 virus challenge infection, resulting in less body weight loss compared to M2e5x VLPs alone. These results indicate that immune responses to both M2e and HA might provide a strategy of vaccination inducing enhanced protection against avian influenza virus.

As COVID-19 exemplifies, respiratory diseases transmitted through aerosols or droplets are global threats to public health, and respiratory protection measures are essential first lines of infection prevention and control. However, common face masks are single use and can cause cross-infection due to the accumulated infectious pathogens. We developed salt-based formulations to coat membrane fibers to fabricate antimicrobial filters. Here, we report a mechanistic study on salt-induced pathogen inactivation. The salt recrystallization following aerosol exposure was characterized over time on sodium chloride (NaCl), potassium sulfate (K2SO4), and potassium chloride (KCl) powders and coatings, which revealed that NaCl and KCl start to recrystallize within 5 min and K2SO4 within 15 min. The inactivation kinetics observed for the H1N1 influenza virus and Klebsiella pneumoniae matched the salt recrystallization well, which was identified as the main destabilizing mechanism. Additionally, the salt-coated filters were prepared with different methods (with and without a vacuum process), which led to salt coatings with different morphologies for diverse applications. Finally, the salt-coated filters caused a loss of pathogen viability independent of transmission mode (aerosols or droplets), against both DI water and artificial saliva suspensions. Overall, these findings increase our understanding of the salt-recrystallization-based technology to develop highly versatile antimicrobial filters.

BackgroundDespite the extensive endeavours, developing an effective malaria vaccine remains as a great challenge. Apical membrane antigen 1 (AMA-1) located on the merozoite surface of parasites belonging to the genus Plasmodium is involved in red blood cell invasion.MethodsInfluenza virus-like particle (VLP) vaccines containing codon-optimized or native (non-codon optimized) AMA-1 from Plasmodium berghei were generated. VLP-induced protective immunity was evaluated in a mouse model.ResultsMice immunized with VLP vaccine containing the codon-optimized AMA-1 elicited higher levels of P. berghei-specific IgG and IgG2a antibody responses compared to VLPs containing non-codon optimized AMA-1 before and after challenge infection. Codon-optimized AMA-1 VLP vaccination induced higher levels of CD4+ T cells, CD8+ T cells, B cells, and germinal centre cell responses compared to non-codon optimized AMA-1 VLPs. Importantly, the codon-optimized AMA-1 VLP vaccination showed lower body weight loss, longer survival and a significant decrease in parasitaemia compared to non-codon optimized VLP vaccination.ConclusionOverall, VLP vaccine expressing codon-optimized AMA-1 induced better protective efficacy than VLPs expressing the non-codon optimized AMA-1. Current findings highlight the importance of codon-optimization for vaccine use and its potential involvement in future malaria vaccine design strategies.