Journal Article

Efficacy of PLGA microparticle-encapsulated formalin-killed Aeromonas hydrophila cells as a single-shot vaccine against A. hydrophila infection

Jun, Jin Woo, Kim, Sang Wha, Kim, Sang Geun, Park, Se Chang, Yun, Saekil, Giri, Sib Sankar, Kim, Hyoun Joong, Chi, Cheng

2017

Overview

Control and prevention of disease is a high priority in aquaculture, and vaccination is important to prevent outbreaks. Here, poly(d,l-lactide-co-glycolic acid) (PLGA) microparticles (MPs) approximately 36μm in diameter were used to encapsulate and deliver Aeromonas hydrophila formalin-killed cells (FKC) as an antigen, and the innate and adaptive immune responses of cyprinid loaches and common carp were assessed following vaccination. The antigen was confirmed to be well encapsulated by scanning electron microscopy analysis of PLGA MP sections. Blood and head kidney specimens were collected and analyzed for bacterial agglutination activity and relative mRNA expression of immune-related genes (IL-1β, IL-10, TNF-α, lysozyme C, TGF-β, and IgM) at 2, 4, 6, and 8weeks post vaccination (wpv). For both fish species, the curve of antibody titer over time was shallower in the PLGA group than the FKC group. These titers in loaches and carp were very similar in the two vaccination groups until 8 and 6 wpv, respectively, but differences were subsequently noted in both species until the end of experiment. Loaches and carp were then challenged with A. hydrophila at 12 and 20 wpv, and 10 and 14 wpv, respectively, and relative survival rates were calculated. For both species, the PLGA groups demonstrated higher survival rates at all time points. Relative expression of IL-1β and TNF-α mRNA was significantly upregulated in the PLGA group at 2 and 4 wpv. Moreover, PLGA-MP vaccination increased relative mRNA levels of lysozyme C and IgM, which were significantly higher than those observed with FKC treatment at 2 wpv and 4, 6, and 8 wpv, respectively. In conclusion, PLGA-MP vaccines have the potential to induce longer and more potent immune responses than FKCs alone, and protect both cyprinid loaches and common carp with greater efficiency.

• Publisher: Elsevier Ltd,Elsevier Limited
• Subject: Adaptive immunity / Aeromonas hydrophila / Aeromonas hydrophila - immunology / Agglutination / Allergy and Immunology / Animals / antibodies / antigens / Aquaculture / Bacteria / Bacterial Vaccines - administration & dosage / Bacterial Vaccines - immunology / blood / Carp / Carps / Cobitidae / Cypriniformes / Cyprinus carpio / Disease control / disease prevention / Drug Carriers - administration & dosage / Effectiveness / Electron microscopy / Encapsulation / Fish / Fish Diseases - prevention & control / Formaldehyde / Gene expression / gene expression regulation / genes / Glycolic acid / Gram-Negative Bacterial Infections - prevention & control / Gram-Negative Bacterial Infections - veterinary / Immune response / Immunoglobulin M / Immunologic Factors - analysis / Immunologic Factors - blood / Interleukin 10 / interleukin-1beta / Kidney / Kidneys / Lactic Acid - administration & dosage / Lysozyme / messenger RNA / Microparticles / Misgurnus anguillicaudatus / Outbreaks / Poly(d,l-lactide-co-glycolic acid) / Polyglycolic Acid - administration & dosage / Polylactide-co-glycolide / Scanning electron microscopy / Shot / Survival / Survival Analysis / survival rate / transforming growth factor beta / Tumor necrosis factor / tumor necrosis factor-alpha / vaccination / Vaccines / Vaccines, Inactivated - administration & dosage / Vaccines, Inactivated - immunology