Isoprinosine as a foot-and-mouth disease vaccine adjuvant elicits robust host defense against viral infection through immunomodulation.

Background: Commercial foot-and-mouth disease (FMD) vaccines have limitations, such as local side effects, periodic vaccinations, and weak host defenses. To overcome these limitations, we developed a novel FMD vaccine by combining an inactivated FMD viral antigen with the small molecule isoprinosine, which served as an adjuvant (immunomodulator). Method: We evaluated the innate and adaptive immune responses elicited by the novel FMD vaccine involved both in vitro and in vivo using mice and pigs. Results: We demonstrated isoprinosine-mediated early, mid-term, and long-term immunity through in vitro and in vivo studies and complete host defense against FMD virus (FMDV) infection through challenge experiments in mice and pigs. We also elucidated that isoprinosine induces innate and adaptive (cellular and humoral) immunity via promoting the expression of immunoregulatory gene such as pattern recognition receptors [PRRs; retinoic acid-inducible gene (RIG)-I and toll like receptor (TLR)9], transcription factors [T-box transcription factor (TBX)21, eomesodermin (EOMES), and nuclear factor kappa B (NF-kB)], cytokines [interleukin (IL)-12p40, IL-23p19, IL-23R, and IL-17A)], and immune cell core receptors [cluster of differentiation (CD)80, CD86, CD28, CD19, CD21, and CD81] in pigs. Conclusion: These findings present an attractive strategy for constructing novel FMD vaccines and other difficult-to-control livestock virus vaccine formulations based on isoprinosine induced immunomodulatory functions.

Bestatin, A Pluripotent Immunomodulatory Small Molecule, Drives Robust and Long-Lasting Immune Responses as an Adjuvant in Viral Vaccines.

An inactivated whole-virus vaccine is currently used to prevent foot-and-mouth disease (FMD). Although this vaccine is effective, it offers short-term immunity that requires regular booster immunizations and has several side effects, including local reactions at the vaccination site. To address these limitations, herein, we evaluated the efficacy of bestatin as a novel small molecule adjuvant for inactivated FMD vaccines. Our findings showed that the FMD vaccine formulated with bestatin enhanced early, intermediate-, and particularly long-term immunity in experimental animals (mice) and target animals (pigs). Furthermore, cytokines (interferon (IFN)α, IFNß, IFNγ, and interleukin (IL)-29), retinoic acid-inducible gene (RIG)-I, and T-cell and B-cell core receptors (cluster of differentiation (CD)28, CD19, CD21, and CD81) markedly increased in the group that received the FMD vaccine adjuvanted with bestatin in pigs compared with the control. These results indicate the significant potential of bestatin to improve the efficacy of inactivated FMD vaccines in terms of immunomodulatory function for the simultaneous induction of potent cellular and humoral immune response and a long-lasting memory response.

The role of zinc sulfate in enhancing cellular and humoral immune responses to foot-and-mouth disease vaccine.

Foot-and-mouth disease (FMD) is a rapidly propagating infectious disease of cloven-hoofed animals, especially cattle and pigs, affecting the productivity and profitability of the livestock industry. Presently, FMD is controlled and prevented using vaccines; however, conventional FMD vaccines have several disadvantages, including short vaccine efficacy, low antibody titers, and safety issues in pigs, indicating the need for further studies. Here, we evaluated the efficacy of a novel bivalent vaccine containing zinc sulfate as an immunostimulant and FMD type O and A antigens (O PA2 and A YC, respectively) against FMD virus in mice and pigs. Zinc sulfate induced cellular immunity in murine peritoneal exudate cells (PECs) and porcine peripheral blood mononuclear cells (PBMCs) by increasing IFNγ secretion. Additionally, FMD vaccine containing O PA2 and A YC antigens and zinc sulfate induced early, mid-, and long-term immune responses in mice and pigs, and enhanced cellular and humoral immunity by regulating the expression of pathogen recognition receptors (PRRs), transcription factors, co-stimulatory molecules, and cytokines in porcine PBMCs from vaccinated pigs. Overall, these results indicated that the novel immunostimulant zinc sulfate induced potent cellular and humoral immune responses by stimulating antigen-presenting cells (APCs) and T and B cells, and enhanced long-term immunity by promoting the expression of co-stimulatory molecules. These outcomes suggest that zinc sulfate could be used as a novel vaccine immunostimulant for difficult-to-control viral diseases, such as African swine fever (ASF) or COVID-19.

Synergistic effect of ribavirin and vaccine for protection during early infection stage of foot-and-mouth disease.

In many countries, vaccines are used for the prevention of foot-and-mouth disease (FMD). However, because there is no protection against FMD immediately after vaccination, research and development on antiviral agents is being conducted to induce protection until immunological competence is produced. This study tested whether well-known chemicals used as RNA virus treatment agents had inhibitory effects on FMD viruses (FMDVs) and demonstrated that ribavirin showed antiviral effects against FMDV in vitro/in vivo. In addition, it was observed that combining the administration of the antiviral agents orally and complementary therapy with vaccines synergistically enhanced antiviral activity and preserved the survival rate and body weight in the experimental animals. Antiviral agents mixed with an adjuvant were inoculated intramuscularly along with the vaccines, thereby inhibiting virus replication after injection and verifying that it was possible to induce early protection against viral infection prior to immunity being achieved through the vaccine. Finally, pigs treated with antiviral agents and vaccines showed no clinical signs and had low virus excretion. Based on these results, it is expected that this combined approach could be a therapeutic and preventive treatment for early protection against FMD.

Effects of Schisandra chinensis extract on the contractility of corpus cavernosal smooth muscle (CSM) and Ca2+ homeostasis in CSM cells.

UNLABELLED: What's known on the subject? And what does the study add? Schisandra chinensis extract (SCE) has been known to have relaxative effects on penile smooth muscle. A recent study showed that SCE could enhance slidenafil citrate-induced relaxation of penile corpus cavernosum. The current study investigated the mechanism of action of SCE and its constituents on corporal smooth muscle cells. And this study shows that SCE induced relaxation of CSM primarily through an endothelium independent pathway and the relaxation effects of SCE on corporal smooth muscle are, in part, due to the activation of K(+) channels and inhibition of TRPC6 channels, resulting in decreased [Ca(2+)]. OBJECTIVE: • To evaluate the relaxant effects of Schisandra chinensis extract (SCE) on corporal tissue in the penis and to investigate the mechanism of action of SCE and its constituents on corporal smooth muscle (CSM) cells. MATERIALS AND METHODS: • The fruit of SC was collected and extracted with ethanol. Six SC lignans (schisandrol A, schisandrol B, schisandrin A, schisandrin B, gomisin N, and schisandrin C) were isolated and purified, and the chemical structures were confirmed by (1)H-nuclear magnetic resonance (NMR) and (13)C-NMR data. • Isolated rabbit CSM strips were mounted in an organ-bath system, and the effects of SCE were evaluated. • To estimate the intracellular Ca(2+) level ([Ca(2+)](i)), we used a Fura-2 fluorescent technique, and a conventional whole-cell patch-clamp technique was used to measure the calcium-sensitive K(+) channels (K(Ca)), inward rectifier K(+) channels (K(IR)), and canonical transient receptor potential cation channel 6 (TRPC6) currents. RESULTS: • SCE induced concentration-dependent relaxation in contracted CSM tissue, and the removal of the endothelium did not significantly affect their relaxation potencies. • In CSM cells, extracellular application of SCE significantly increased whole-cell K(Ca) currents (117.4%) and K(IR) currents (110.0%). These effects were completely abolished by charybdotoxin or BaCl(2). • In contrast, carbachol-induced TRPC6 channel activity was significantly inhibited (87.3%) by SCE in green fluorescent protein-TRPC6 pcDNA transfected HEK 293 cells. [Ca(2+)](i) measurements showed that SCE effectively reduced basal [Ca(2+)](i) in both cell lines (CSM cells and A7r5 cells) and the [Arg8]-vasopressin (AVP)-induced [Ca(2+)](i) increase in A7r5 cells. • Among the six SC lignans, schisandrin A and schisandrin B most effectively attenuated the AVP-induced [Ca(2+)](i) increase. CONCLUSIONS: • SCE induced relaxation of CSM that occurred primarily via an endothelium-independent pathway. • The relaxation effects of SCE on CSM were, in part, due to the activation of K(+) channels and inhibition of TRPC6 channels, resulting in decreased [Ca(2+)](i).