Nanoparticle delivery of a tetravalent E protein subunit vaccine induces balanced, type-specific neutralizing antibodies to each dengue virus serotype.

Dengue virus (DENV) is the causative agent of dengue fever and dengue hemorrhagic shock syndrome. Dengue vaccine development is challenging because of the need to induce protection against four antigenically distinct DENV serotypes. Recent studies indicate that tetravalent DENV vaccines must induce balanced, serotype-specific neutralizing antibodies to achieve durable protective immunity against all 4 serotypes. With the leading live attenuated tetravalent DENV vaccines, it has been difficult to achieve balanced and type-specific responses to each serotype, most likely because of unbalanced replication of vaccine viral strains. Here we evaluate a tetravalent DENV protein subunit vaccine, based on recombinant envelope protein (rE) adsorbed to the surface of poly (lactic-co-glycolic acid) (PLGA) nanoparticles for immunogenicity in mice. In monovalent and tetravalent formulations, we show that particulate rE induced higher neutralizing antibody titers compared to the soluble rE antigen alone. Importantly, we show the trend that tetravalent rE adsorbed to nanoparticles stimulated a more balanced serotype specific antibody response to each DENV serotype compared to soluble antigens. Our results demonstrate that tetravalent DENV subunit vaccines displayed on nanoparticles have the potential to overcome unbalanced immunity observed for leading live-attenuated vaccine candidates.

Effect of leptin on expression of lipoic acid synthase in the liver and kidney of Leprdb/dbmice / 中国实验动物学报

Objective To study the expression of lipoic acid synthase(LIAS)in the liver and kidney of Leprdb/db mice with deficient leptin receptor. Methods Eight 10-week old male Leprdb/ +mice and Leprdb/dbmice were included in this study. The body weight of rats in the two groups was measured. Fasting blood glucose(FPG)was measured with blood glucose test strips for all mice after fasting for 8 hours. Blood samples were obtained from the abdominal aorta and the animals were sacrificed. The liver and kidney were weighed. The right lobe of liver and the left kidney samples were fixed in 4% paraformaldehyde for pathological examination. Serum samples were separated and the sereum contents of CHO, TG,HDL and LDL were detected. The mitochondria of liver and kidney tissues were extracted with a mitochondrial isolation kit, and the protein was extracted. The expression of LIAS protein was detected by western blot. Results Histopathological observation showed that the liver and kidney tissues of Leprdb/ +mice have intact and clear structure. But the liver tissue of Leprdb/dbmice showed fatty degeneration, the kidney tissue showed glomerular hypertrophy, basement membrane thickening, mesangial area widened, including mesangial cells and mesangial matrix increased. The GLU,CHO,TG,LDL and AST of Leprdb/dbmice were significantly increased compared with those of Leprdb/ +mice(P<0.05). Compared with Leprdb/ +mice,the LIAS protein expression was significantly increased in the liver and kidney mitochondria of Leprdb/dbmice(P<0.05). Conclusions There is impaired glucose and lipid metabolism in the Leprdb/dbmice which has defect leptin receptor,and the expression of LIAS protein in liver and kidney of the Leprdb/dbmice is higher than that of Leprdb/ +mice.

Genotyping of the offsprings of Leprdb/ +mice by TaqMan probe fluorescence quantitative PCR / 中国实验动物学报

Objective To establish an efficient method of genotyping for Leprdb/ +mouse offsprings by TaqMan probe quantitative fluorescence PCR. Methods Genome DNA was extracted from tails of 228 Leprdb/ +mouse offsprings. PCR primers and TaqMan probes were designed according to the mutation sites of Lepr gene(rs1801133). Real time PCR assay was applied and SNP loci were typed with SDS software. The genotyping of 2-month old Leprdb/dbmice was validated by the phenotype and Hardy-Weinberg equilibrium test was performed. Results 228 samples were detected by the established TaqMan fluorescence quantitative PCR assay. 64 mice were of GG genotype, with a genotype frequency of 0.1929. 123 mice were of GT genotype, with a genotype frequency of 0.5395. 41 mice were of TT genotype, with a genotype frequency of 0.2807. Compared with the phenotype typing,the sensitivity of the TaqMan fluorescence quantitative PCR was 97.56% and the specificity was 99.47%. Conclusions TaqMan probe quantitative fluorescence PCR assay is a simple and efficient method,and can be used to detect the genotype of Leprdb/ +mouse offsprings.