Layered double hydroxide nanoparticles as an adjuvant for inactivated foot-and-mouth disease vaccine in pigs

Abstract

Background Foot-and-mouth disease (FMD) is a highly transmissible disease that leads to vast economic losses in many countries. Prevention using inactivated vaccines is one effective measure used to control FMD. Unfortunately, inactivated FMD vaccines provide only short-term protection and require a cold-chain system. In recent years, many studies have shown that layered double metal hydroxides (LDHs) carrying antigens can be used to strongly induce immune responses. In this study, LDH nanoparticles (NPs) were prepared by hydrothermal synthesis. LDH particle size, electric potential, and morphology were measured and observed. The adsorption capacity of LDH NPs to FMDV was tested. The effects of LDH as an adjuvant on inactivated FMDV vaccines were further evaluated and compared with commercial FMDV Montanide ISA-206 in BALB/C female mice and Yorkshire pigs. Results LDH NPs were successfully prepared with a uniform particle size of ~ 87.21 nm, regular edges, a loose hexagonal shape and positive zeta charge of 32 mV. The maximum absorption concentration was 0.16–0.31 μg FMDV/μg LDH. In the mouse experiment, antibody levels in group LDH + FMDV were significantly higher compared to group saline + FMDV (P < 0.01) from days 42–98 and were significantly higher to group ISA-206 + FMDV on day 56 post-immunization (P < 0.05). After day 14 post-immunization, IFN-γ content was significantly increased (P < 0.05). In the pig experiment, antibody levels in both the ISA-206 + FMDV and LDH + FMDV were positive and were significantly higher compared with the PBS group on day 7 (P < 0.005). Antibody levels in 90% pigs were positive on day 56 in the LDH group. The neutralizing antibody levels in the LDH and ISA-206 groups were significantly higher from days 7–28 compared to the PBS control group (P < 0.05). Thus, LDH NPs were effective at inducing an immune response against FMDV. Conclusions LDHs with a loose hexagonal shape and a positive charge were prepared and evaluated as adjuvant for FMD vaccine. It was demonstrated that LDHs can induce immune responses in mice and pigs. In addition, the LDHs produced antibodies continuously which may indicate a slow-release effect. The study shows that LDHs may act as a potentially useful FMDV adjuvant.

Mg/Al-LDH as a nano-adjuvant for pertussis vaccine: a evaluation compared with aluminum hydroxide adjuvant

“…Chen et al report that LDH nanoparticles could load three recombinant antigens IB, PAg1, PAg2 of pathogenic E. coli simultaneously, and the multiple-antigen loading induced a much more effective antibody response than a single antigen [22]. Moreover, LDH nanoparticle could also act as an antigen carrier for inactivated foot-and-mouth disease virus with saturated adsorption of 0.16-0.31 mg mg −1 , inducing an effective immune response in mice and pigs [27]. Here, we showed that the maximum adsorption of Mg/Al-LDH for OVA was about 0.5 mg mg −1 , which demonstrated the excellent antigen adsorption ability of LDH nanoparticles as described in previous reports [20,22,23].…”

“…Nanomaterials have been demonstrated to act as excellent vaccine adjuvants due to their desirable physicochemical properties, safety and immune regulation capacity, such as silica nanoparticles [11], chitosan nanoparticles [12], PLGA nanoparticles [13, 14,] and layered double hydroxide (LDH) [15,16]. LDH has a special hydrotalcite-like layered structure with trivalent/divalent metal cations as hydroxide layer and exchangeable anions located at interlayer [17].…”

The Recombinant Expression Proteins FnBP and ClfA From Staphylococcus aureus in Addition to GapC and Sip From Streptococcus agalactiae Can Protect BALB/c Mice From Bacterial Infection

“…The proteins were diluted in PBS and thoroughly mixed with a nano-adjuvant in a 1:1 ratio to obtain FC, GS, and FCGS nano-adjuvant vaccines. We previously screened nano-adjuvants to identify immunological effects of the nano-adjuvants compared with ordinary adjuvants ( 27 ). BALB/c mice were randomly divided into six groups, with six mice in each group.…”

Layered Double Hydroxides as the Unique Product of Target Ionic Construction for Energy, Chemical, Foods, Cosmetics, Medicine and Ecology Applications

“…The use of LDHs as adjuvants is also actively developing. [218][219][220] Thus, various LDHs are highly effective for administering vaccines against Newcastle disease, [221] pertussis, [222] foot-and-mouth disease, [223] ovalbumin for antitumor goals, [224] etc.…”