Research Insight - Developing a Nanoparticle Vaccine for Spring Viremia of Carp Virus Infection with the Aniview100

Bin Zhu’s team from Northwest A&F University has made new progress in developing a nanoparticle vaccine platform for spring viremia of carp virus. The research results have been published in Microbiology Spectrum (IF=9.043,Q2).

The carp spring viremia (SVC) caused by the spring viremia of carp virus (SVCV) has become a serious threat to the carp aquaculture industry worldwide, causing huge economic losses. It has been proven that DNA vaccines have the ability to generate long-term humoral and cellular immune responses, making them one of the most promising applications for the prevention and treatment of infectious pathogens, including SVC and other viral diseases. However, its effectiveness in clinical trials has been disappointing. This is because DNA vaccines have some drawbacks, including being easily degraded by DNA enzymes and lysosomes, uneven distribution after injection of DNA vaccines, and low expression efficiency, all of which hinder their clinical development.

Many polymers are used as nanoparticles for DNA vaccine delivery. PLGA (poly(D,L-lactide-co-glycolide)) is a biodegradable, biocompatible, and non-toxic polymer composed of three different hydroxyl acid monomers (D-lactic acid, lactic acid, and glycolic acid). PLGA has been considered an attractive vaccine antigen carrier and adjuvant; Chitosan is a natural polysaccharide product that removes some acetyl groups and has various properties, such as biodegradability, biocompatibility, non toxicity, bioadhesiveness, and immune enhancement. Due to these characteristics, chitosan is considered a very promising drug/antigen carrier for delivering proteins, peptides, nucleic acids, etc.

Among the various important receptors on the surface of antigen-presenting cells (APCs), mannose receptors are important pattern recognition and intracellular receptors, with multiple extracellular domains that can recognize and bind to various endogenous and exogenous ligands. In addition, due to its high affinity and high-level expression on the surface of APCs, mannose receptors are widely used as targets for antigen delivery.

In the research of Professor Bin Zhu's team, a dual-targeted polymer nanovaccine (MCS-PCHG) was prepared using chitosan coated PLGA nanoparticles coated with mannose. The vaccine encodes an antigen (G131c) for a highly infectious and fatal disease (Cyprinus viremia, SVC), as well as the heavy chain C3 region (CH3) of carp immunoglobulin M (IgM). The dual targeted polymer nanovaccine consists of two targeting ligands, and mannose can specifically bind to the mannose receptor on the surface of APC; After translation and expression in the host, CH3 can interact with Fc receptors on APCs. This vaccine has good biocompatibility, which can promote the activation of APC and induce a strong adaptive immune response to combat SVCV infection.

▲ Schematic illustration of mannosylated chitosan/chitosan-based nanovaccine

Randomly select carp (weighing around 1.2g) and inject Rhodamine labeled nanovaccines (RBI-PCHG, RBI-CS-PCHG, and RBI-MCS-PCHG) into the abdominal cavity at a dose of 2mg/g (body weight). Use the AniView multimodal in vivo animal imaging system to detect the retention time of RBI labeled nanovaccines in carp at different time points (0, 6, 12, 24, 72, 120, 168, and 240 hours) after vaccination. Fish inoculated with PCHG, CS-PCHG, and MCS-PCHG showed similar fluorescence intensity during the initial stage of inoculation (0 hours) and 120 hours after inoculation. From 6 to 72 hours after vaccination, fish inoculated with MCS-PCHG showed more significant vaccine retention than the CS-PCHG and PCHG groups (p<0.05).

▲ (F) Biodistribution of RBI-PCHG, RBI-CSPCHG, and RBI-PCHG nanovaccine in vaccinated fish at different time points. (G) Quantitative fluorescence signals in different vaccinated fish. Data are represented as means 6 the SD (n = 3). Different lowercase letters (a, b, and c) indicate significant differences (P , 0.05).

Reference

10.1128/spectrum.03085-22