Lycium barbarum polysaccharides as an adjuvant for recombinant vaccine through enhancement of humoral immunity by activating Tfh cells.

Lycium barbarum polysaccharides (LBP) have been shown to play a variety of immune-modulatory functions which include activation of T and B cells. Follicular helper T (Tfh) cells are now recognized as a subset of helper T cells which regulate the multiple stages of B cell maturation and function. In our current study, we found that LBP were able to activate CXCR5+PD-1+ Tfh cells and induce IL-21 secretion. At the same time LBP also promoted the formation of germinal centers (GC) and production of GL-7+B220+GC B cells. LBP as an adjuvant could increase generation of rAd5VP1-induced Tfh cells. Our results indicate that LBP might enhance T cell-dependent Ab responses by acting as an adjuvant for the generation of Tfh cells. Future vaccine designs might therefore be targeted to induce strong antigen-specific Tfh responses in order to boost its protective effects.

Bioluminescence imaging allows monitoring hepatitis C virus core protein inhibitors in mice.

BACKGROUND: The development of small molecule inhibitors of hepatitis C virus (HCV) core protein as antiviral agents has been intensively pursued as a viable strategy to eradicate HCV infection. However, lack of a robust and convenient small animal model has hampered the assessment of in vivo efficacy of any antiviral compound. METHODOLOGY/PRINCIPAL FINDINGS: The objective of this work was to develop a novel method to screen anti-core protein siRNA in the mouse liver by bioluminescence imaging. The inhibitory effect of two shRNAs targeting the highly conserved core region of the HCV genome, shRNA452 and shRNA523, was examined using this method. In the transient mouse model, the effect of shRNA-523 was detectable at as early as 24 h and became even more pronounced at later time points. The effect of shRNA-452 was not detectable until 48 h post-transduction. In a stable mouse model, shRNA523 reduced luciferase levels by up to 76.4±26.0% and 91.8±8.0% at 6 h and 12 h after injection respectively, and the inhibitory effect persisted for 1 day after a single injection while shRNA-Scramble did not seem to have an effect on the luciferase activity in vivo. CONCLUSIONS/SIGNIFICANCE: Thus, we developed a simple and quantitative assay for real-time monitoring of HCV core protein inhibitors in mice.

Bursin as an adjuvant is a potent enhancer of immune response in mice immunized with the JEV subunit vaccine.

Adjuvants play an important role in the formulation of effective and appropriate vaccines. A series of synthetic bursin and bursin-like peptides was heterologously expressed in Escherichia coli. The use of bursin as an adjuvant enhanced the specific immune responses of mice immunized with a recombinant Japanese encephalitis virus E-binding domain (JEV E-BD) fusion protein. The effect was determined in the form of protective anti-JEV E titers, antibodies (IgG1 and IgG2a), spleen cell lymphocyte proliferation, the levels of interferon-gamma and interleukin-4 cytokines, and the T-lymphocyte sub-type composition. The IgG2a titer and interferon-gamma level suggested that the E-BD protein potentiates the Th1 immune response. These responses were changed when the immunogen was combined with one of the synthetic peptides as adjuvant. JEV-neutralization assay results show that the presence of bursin significantly enhance the JEV-neutralizing titer. We conclude that bursin as an adjuvant is a potent enhancer of immune response in mice immunized with the JEV subunit vaccine, and represents a promising adjuvant for vaccination.

[Fusion expression of O type foot-and-mouth diseases virus VP1 gene and HSP70 gene and induction of immune responses in mice].

Vp1 gene of O type foot-and-mouth diseases virus and M. tuberculosis HSP70 were expressed in methylotrophic yeast Pichia pastoris expression system. The results of cellular immune responses and humoral immune response were examined after BALB/c mice were immunized with fusion protein expressed in methylotrophic yeast Pichia pastoris. The genes was cloned into the vector pPICZalpha-A by routine molecular technique. The plasmid fusion (pPICZalphaA-vp1-HSP70) was created that HSP70 located downstream of VP1 gene of O type foot-and-mouth disease virus. Vp1 was expressed by fusing to the amino terminus of M. tuberculosis hsp70 in yeast Pichia pastoris. The recombined fusion plasmid was transformed into methylotrophic yeast Pichia pastoris X-33 by electrophoration. The recombinant transformants were selected by Zeocin and induced by the addition of methanol every 24h. The expressived product analyzed by SDS-PAGE and Western blotting. The result indicated that the fusion protein(vp1-HSP70) has specific antigenicity. Mice were inoculated transcutaneous three times at a two-weeks interval with fusion protein, PBS and conventional inactivated vaccines. To evaluate the prophylaxtic efficacy of fusion protein, Titers of antibodies was detected by ELISA and proliferation of lymphocytes were determined by MTT. The results indicated that fusion protein could elicit specific humoral immune and cellular immune responses. Compared with conventional inactivated vaccines, fusion protein elicited slightly lower FMDV antibody level but stronger T cell proliferation.