[Gene sequence and antigenic epitope variation within the F protein of respiratory syncytial virus in Sichuan, China].

OBJECTIVE: To investigate the variation of cytotoxic T-lymphocyte (CTL) and neutralizing epitopes in F protein of respiratory syncytial virus (RSV) isolated in Sichuan. METHODS: Nearly full-length of F protein gene of 10 strains of RSV isolated in Sichuan was amplified by RT-PCR and sequenced. The genetic variations, especially the CTL and neutralizing antibody epitopes within different subtypes and genotypes were analyzed and compared. RESULTS: The F protein of RSV is highly conserved within the two subtypes, with the P-distances of nucleotide and amino acids were 0.102 +/- 0.005 and 0.058 +/- 0.006, respectively. Neutralizing epitopes 47F and L4 were conserved between the subtypes, but RS-348 and 7C2 were only conserved within the subtypes. CTL epitopes HLA B * 57, HLA A * 01 and HLA Cw * 12 were conserved only within subtype A. There were specific different sites between the subtypes. CONCLUSION: The sequences of F protein from Sichuan RSV isolates were highly conserved, so as the epitopes on F-protein within subtypes, the identified CLT epitopes in subtype A may not be recognized in subtype B virus.

Engineered pH-responsive hydrazone-carboxylate complexes-encapsulated 2D matrices for cathepsin-mediated apoptosis in cancer.

Spurred by the current advancements in engineering various intelligent nanoparticle-based drug delivery systems, conjugation of drugs with the stimuli-responsive molecular switches has become one of the most efficient approaches to deliver a drug cargo in spatiotemporal controlled fashions. In this study, we fabricated an innovative pH-triggered hydrazone-carboxylate complex of doxorubicin (Dox), which was subsequently encapsulated in the layered double hydroxide (LDH) nanoparticles for effective cancer therapeutics. These two-dimensional (2D) biodegradable matrices efficiently delivered Dox by pH-triggered release in the acidic lysosomal environment and their subsequent escape to cytosol. Moreover, the delivered Dox molecules and high positively-charged surfaces of LDHs facilitated the cancer cell ablation via enhancing the cathepsins-mediated cell apoptosis assisted by free radical species generation. The critical advancements in the nanoparticle-based designs and substantial ablation of tumor cells through a free radical attack indicate that the designed pH-triggered drug composites can be used for efficient cancer therapeutics. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1184-1194, 2019.