To prepare tubeimoside Ⅲ nanoemulsion (TBMⅢ-NE) and evaluate its adjuvant effect in vaccines.
TBMⅢ-NE was prepared using low-energy emulsification. Dynamic light scattering was used to characterize the particle size and polydispersity index of the obtained TBMⅢ-NE, and transmission electron microscopy (TEM) was employed to observe the morphology. CCK-8 assay was utilized to determine the cytotoxicity of TBMⅢ-NE on bone marrow-derived dendritic cells (BMDCs). The in vitro safety of TBMⅢ-NE was evaluated using a hemolysis assay. The ability of TBMⅢ-NE to promote the phagocytosis of antigens by DC2.4 cells was observed using confocal laser microscopy. After co-incubation of TBMⅢ-NE with BMDCs, the expression levels of CD40, CD86, MHC-Ⅰ, and CCR7 on the surface of BMDCs were detected using flow cytometry, and the levels of cytokines in the supernatant of BMDCs were measured using enzyme-linked immunosorbent assay (ELISA). After female BALB/c mice were immunized with the SARS-CoV-2 antigen RBD in combination with TBMⅢ-NE, ELISA was conducted to determine the serum levels of specific IgG, IgG2a, and IgG1 antibodies. The number of specific IFN-γ-secreting cells in mouse splenocytes was detected using enzyme-linked immunospot (ELISpot) assay.
The prepared blank nanoemulsion (BNE) and TBMⅢ-NE were in a particle size of 25.46 and 25.89 nm, and a polydispersity index of 0.214 and 0.125, respectively. TEM displayed that TBMⅢ-NE was in uniform sphere and well dispersed. When the TBMⅢ-NE adjuvant was diluted by 400-fold, the survival rate of BMDCs was approximately 86%. Compared with free TBMⅢ, the hemolytic toxicity of TBMⅢ-NE was significantly reduced (P<0.01). TBMⅢ-NE promoted the phagocytosis of antigens by DC2.4 cells and significantly increased the expression of CCR7 on the surface of BMDCs (P<0.05), indicating its potential to promote more dendritic cells to effectively migrate to lymph nodes. TBMⅢ-NE also promoted the expression of IL-6 and IL-1β in the supernatant of BMDCs (P<0.05). When combined with RBD, TBMⅢ-NE significantly increased the levels of specific IgG, IgG2a, and IgG1 antibodies in mouse serum (P<0.01) and promoted the secretion of specific IFN-γ in splenocytes (P<0.01), indicating that TBMⅢ-NE could enhance specific cellular immune responses.
A stable and highly effective TBMⅢ-NE that can induce humoral and cellular immune responses is successfully prepared.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |