Induction of Th1 and Th2 in the protection against SARS-CoV-2 through mucosal delivery of an adenovirus vaccine expressing an engineered spike protein.

A series of recombinant human type 5 adenoviruses that express the full-length or membrane-truncated spike protein (S) of SARS-CoV-2 (AdCoV2-S or AdCoV2-SdTM, respectively) was tested the efficacy against SARS-CoV-2 via intranasal (i.n.) or subcutaneous (s.c.) immunization in a rodent model. Mucosal delivery of adenovirus (Ad) vaccines could induce anti-SARS-CoV-2 IgG and IgA in the serum and in the mucosal, respectively as indicated by vaginal wash (vw) and bronchoalveolar lavage fluid (BALF). Serum anti-SARS-CoV-2 IgG but not IgA in the vw and BALF was induced by AdCoV2-S s.c.. Administration of AdCoV2-S i.n. was able to induce higher anti-SARS-CoV-2 binding and neutralizing antibody levels than s.c. injection. AdCoV2-SdTM i.n. induced a lower antibody responses than AdCoV2-S i.n.. Induced anti-S antibody responses by AdCoV2-S via i.n. or s.c. were not influenced by the pre-existing serum anti-Ad antibody. Novelty, S-specific IgG1 which represented Th2-mediated humoral response was dominantly induced in Ad i.n.-immunized serum in contrast to more IgG2a which represented Th1-mediated cellular response found in Ad s.c.-immunized serum. The activation of S-specific IFN-É£ and IL-4 in splenic Th1 and Th2 cells, respectively, was observed in the AdCoV2-S i.n. and s.c. groups, indicating the Th1 and Th2 immunity were activated. AdCoV2-S and AdCoV2-SdTM significantly prevented body weight loss and reduced pulmonary viral loads in hamsters. A reduction in inflammation in the lungs was observed in AdCoV-S via i.n. or s.c.-immunized hamsters following a SARS-CoV-2 challenge. It correlated to Th1 cytokine but no inflammatory cytokines secretions found in AdCoV-S i.n. -immunized BALF. These results indicate that intranasal delivery of AdCoV2-S vaccines is safe and potent at preventing SARS-CoV-2 infections.

The photothermal effect of silica-carbon hollow sphere-concanavalin A on liver cancer cells.

Hepatocellular carcinoma (HCC) is one of the most common cancers and causes of death by cancer. Concanavalin A (ConA) lectin can specifically bind to the glycoprotein receptors of HCC, which are produced by the aberrant overexpression of liver cancer cells. ConA was used in the current study to conjugate on silica-carbon hollow spheres (SCHSs) and applied in the thermal ablation therapy of liver cancer cell lines under near-infrared (NIR) laser irradiation. We found that the amount of ConA-SCHS complex binding to hepatoma cells was significantly higher than that seen with normal hepatocytes, based on flow cytometric analysis and confocal imaging. Hepatoma cells incubated with ConA-SCHSs were thus more easily killed by the subsequent irradiation with a NIR laser. The results show that the ConA-SCHS complex may enhance the interaction with highly expressed ConA receptors on hepatoma cells, and thus serve as an effective photothermal therapy agent for liver cancer treatment.