Co-utilization of a TLR5 agonist and nano-formulation of HIV-1 vaccine candidate leads to increased vaccine immunogenicity and decreased immunogenic dose: A preliminary study.

Vaccines currently available for AIDS show poor efficiency, demonstrating the need for new strategies to increase their immunogenicity. In this study, the HIV-1P24-Nef peptide was used as a model vaccine, followed by utilization of a novel strategy to increase its immunogenicity. There is a growing interest in using TLR agonists for vaccine formulations. Such molecules bind to their receptors on immune cells, especially the cell surface of antigen presenting cells, thereby activating these cells and inflammatory responses. In the present study, FLiC (flagellin molecule sequence from Pseudomonas aeruginosa) was used as a TLR5 agonist. In addition, PLGA nanoparticles were used as a transmitter system to enhance vaccine efficiency and its effective transfer to immune systems. In light of this, the P24-Nef peptide was conjugated to FLiC through chemical reactions. The HIV-1P24-Nef/FLiC conjugate was constructed as a nano-vaccine using PLGA particles. Subsequently, mice were immunized intradermally three times with three-week intervals with HIV-p24-Nef/FLiC/PLGA, HIV-p24-Nef/PLGA, FLiC/PLGA, PLGA, and PBS in two doses (20 and 5µg). Three weeks after the last booster injection, cell proliferation was assessed using the Brdu/ELISA assay, and cytotoxicity was evaluated by CFSE and splenocyte cytokine secretion (IL-4 and IFN-γ); in addition, IgG1 and IgG2a antibody isotype titers were determined using a commercial ELISA kit. Our results showed that Co-utilization of TLR5 and nano-particles not only improves vaccine immunogenicity but also decreases the immunogenic dose of vaccine candidate required. We showed that the immune system was effectively stimulated via the nano-vaccination strategy using the TLR5 agonists. The effect of this strategy showed variations in different parameters of the immune system; in this regard, cellular immune responses had a higher stimulation level, compared with humoral immune responses.

Chemical composition and biological activities of Iranian Achillea wilhelmsii L. essential oil: a high effectiveness against Candida spp. and Escherichia strains.

In the case of Achillea wilhelmsii, 30 compounds were identified representing 94.48% of the total oil with a yield of 0.82% w/w. The major constituents of the oil were described as α-thujene (6.11%), α-pinene (5.11%), sabinene (5.23%), p-cymene (7%), 1,8-cineole (6%), linalool (10%), camphor (8.43%), thymol (18.98%) and carvacrol (20.13%). A. wilhelmsii oil exhibited higher antibacterial and antifungal activities with a high effectiveness against Escherichia coli and Candida albicans with the lowest minimum inhibitory concentration and minimum bactericidal concentration/minimum fungicidal concentration value (2 ± 0.0-2 ± 0.0 g/mL, 1 ± 0.5-1 ± 0.5 g/mL), respectively. Results showed that A. wilhelmsii oil exhibits a higher activity in each antioxidant system with a special attention for ß-carotene bleaching test (IC50: 19 µg/mL) and reducing power (EC50: 10 µg/mL). Antioxidant activity-guided fractionation of the oil was carried out by TLC-bioautography screening and fractionation resulted in the separation of main antioxidant compounds which were identified as thymol (65%) and carvacrol (19%). In conclusion, these results support the use of the essential oil and its main compounds for their antioxidant properties and antimicrobial activity.

Chemical composition, antimicrobial and antioxidant activities of the essential oil of Psammogeton canescens.

This study reports the chemical composition, antimicrobial activity and antioxidant properties of Psammogeton canescens essential oil (EO) and its main compounds. The EO was obtained from the aerial parts of P. canescens by hydrodistillation and analysed by using GC/MS. The main constituent was ß-bisabolene (25%), followed by α-pinene (20%), apiole (15.34%), γ-terpinene (7.34%), p-cymene (5.35%), ß-pinene (5.41%), camphene (5.12%), dill apiole (5%), myrcene (4.54%), colchicine (0.56), sylvestrene (0.56%), ß-caryophyllene (0.45%), caryophyllene oxide (0.43%), (Z)-ß-farnesene (0.32%), cembrene (0.21%), folic acid (0.21%), germacrene D (0.14) and ß-sesquiphellandrene (0.13). ß-Bisabolene exhibited strong antioxidant activity (14 ± 0.8 µg/mL). The EO of P. canescens was particularly active against Candida albicans and Escherichia coli, with the lowest minimum inhibitory concentration and minimum bactericidal/fungicidal concentration values. In conclusion, these results support the use of the EO and its main compounds for their antioxidant properties and antimicrobial activity.