Construction and evaluation of DNA vaccine encoding Hantavirus glycoprotein N-terminal fused with lysosome-associated membrane protein.

BACKGROUND: Hantaviral diseases can have a high case fatality rate within the absence of broadly effective antiviral treatments or vaccines. We developed a DNA vaccine targeting the Hantavirus glycoprotein N-terminal (Gn) to major histocompatibility complex class II compartment by fusing the antigen with lysosome-associated membrane protein 1 (LAMP1), which altered antigen presenting pathway and activated the CD4+ T cells. METHODS: The segments of Gn and LAMP1 were cloned into vector pVAX1, and recombinant plasmid was constructed by inserting Gn sequence into LAMP1, between luminal and the transmembrane/cytoplasmic domains. Subsequently, the protein expression was identified through immunoprecipitation, western blot and Immunofluorescent assay. Adaptive immune responses were assessed by the presence of specific and neutralizing antibodies, interferon (ELISpot results, and cytotoxic T-lymphocyte (CTL) cytotoxicity. Epitope mapping was performed to study the T-cell epitopes. Protective immunity in vivo was evaluated using a novel HTNV-challenging model, and safety evaluation was based on histological and behavioral observations. RESULTS: Native or LAMP1 targeting HTNV Gn was successfully identified. Humoral immune responses were enhanced, featuring with satisfying titers of specific and neutralizing antibody production. The boosted activities of IFN-γ and CTL cytotoxicity witnessed enhanced cellular immune responses. Effective protection against HTNV in vivo was conferred in all three vaccine groups by the challenge model. Safety was confirmed and one dominant T-cell epitope screened from immunized mice overlapped the specific T-cell hot spot in HFRS patients. CONCLUSION: LAMP1 targeting strategy successfully enhanced the efficacy of HTNV Gn-based vaccine, which is highly immunogenic and safe, showing promise for immunoprophylaxis against HFRS. Further investigations are warranted in the future.

Intraspecific competition and light effect on reproduction of Ligularia virgaurea, an invasive native alpine grassland clonal herb.

The relationship between sexual reproduction and clonal growth in clonal plants often shows up at the ramet level. However, only a few studies focus on the relationship at the genet level, which could finally account for evolution. The sexual reproduction and clonal growth of Ligularia virgaurea, a perennial herb widely distributed in the alpine grasslands of the Qinghai-Tibetan Plateau of China, were studied under different competition intensities and light conditions at the genet level through a potted experiment. The results showed that: (1) sexual reproduction did not depend on density or light, and increasing clonal growth with decreasing density and increasing light intensity indicated that intraspecific competition and light intensity may affect the clonal life history of L. virgaurea; (2) both sexual reproduction and clonal growth show a positive linear relationship with genet size under different densities and light conditions; (3) a threshold size is required for sexual reproduction and no evidence of a threshold size for clonal growth under different densities and light conditions; (4) light level affected the allocation of total biomass to clonal and sexual structures, with less allocation to clonal structures and more allocation to sexual structures in full sunlight than in shade; (5) light determined the onset of sexual reproduction, and the genets in the shade required a smaller threshold size for sexual reproduction to occur than the plants in full sunlight; and (6) no evidence was found of trade-offs between clonal growth and sexual reproduction under different densities and light conditions at the genet level, and the positive correlation between two reproductive modes indicated that these are two integrated processes. Clonal growth in this species may be viewed as a growth strategy that tends to maximize genet fitness.