Elevated low-density lipoprotein cholesterol (LDL-C) increases the risk of atherosclerotic cardiovascular disease. Peptide-based PCSK9 vaccines have shown a promising prospect of reducing LDL-C. In peptide vaccine (pVax) design, the peptide antigens need to conjugate with carrier protein (CP). However, CP incorporation can induce undesirable anti-CP antibodies, which sterically mask peptide epitopes from being recognized by specific B cells and impair subsequent therapeutically antibody production. This epitopic suppression has posed a barrier in clinical translation of conjugate vaccines all along. A model CP (keyhole limpet hemocyanin, KLH) is herein camouflaged with serum albumin (SA) into hybrid nanocarriers (SA@N), with PCSK9 peptide being anchored onto the surface to form nanovaccine (SA@NVax). Such camouflage of KLH via high “self” SA coverage is able to inhibit KLH from extracellular immune recognition and prevent detectable anti-KLH antibody production. Furthermore, the nanovaccine around 70 nm stabilized by intermolecular disulfide network is ideal for internalization and biodegradation by antigen presenting cells as well as better retention in draining lymph nodes and spleen. As expected, the SA@NVax efficiently primes higher anti-PCSK9 IgG antibody titer than PCSK9 pVax.
Macroalgae are often used to produce sodium alginate, but their by-products have not been fully utilized. This study aimed to optimize the extraction of bound polyphenols (BPs) from Macrocystis pyrifera (L.) residues, analyze the composition of free polyphenols (FPs) and BPs, and evaluate their antioxidant activities and ability to inhibit glycosidase activity. The optimal conditions for extracting BPs achieved by the response surface method were as follows: 50 °C, a solid–liquid ratio of 1:50, an alkaline hydrolysis time of 2.38 h, and a NaOH concentration of 8 mol/L. Polyphenol content determination results indicated that FPs had significantly higher total polyphenols (13.02 ± 0.05 μg GAE/mg) and phlorotannin (3.44 ± 0.04 μg PE/mg) than BPs (6.57 ± 0.07 μg GAE/mg and 1.32 ± 0.20 μg PE/mg). HPLC/ESI-QTOF-MS showed distinct profiles: FPs had one polyhydroxy phenol, nine flavonoids, and four additional compounds, whereas BPs had five flavonoids and four other compounds. Antioxidant activity was found to be higher in FPs than in BPs (DPPH: 3.03 vs. 1.79 μg TE/mg; FRAP: 19.40 vs. 7.43 μg TE/mg). Furthermore, FPs exhibited 4.59- and 11-fold higher inhibition capacity toward α-amylase and α-glucosidase, respectively, compared to BPs. The results provide valuable basic data for the application of macroalgae residues in the marine biological industry and reveal their potential hypoglycemic ability.
危险品化学品经营许可证（带存储）