A novel vaccination strategy against Vibrio harveyi infection in Asian seabass (Lates calcarifer) with the aid of oxygen nanobubbles and chitosan

• Published in: Fish & shellfish immunology 2024-06, Vol.149, p.109557, Article 109557
• Main Authors: Thu Lan, Nguyen Giang, Dong, Ha Thanh, Vinh, Nguyen Tien, Salin, Krishna R., Senapin, Saengchan, Pimsannil, Khaettareeya, St-Hilaire, Sophie, Shinn, Andrew P., Rodkhum, Channarong
• Format: Article
• Language: English
• Subjects: Animals; antibody formation; Antibody response; antigens; Asian seabass; Bacterial Vaccines - administration & dosage; Bacterial Vaccines - immunology; Bass - immunology; blood serum; Chitosan; Chitosan - administration & dosage; fish; Fish Diseases - immunology; Fish Diseases - prevention & control; Lates calcarifer; mucus; nanobubbles; Oxygen; Oxygen nanobubbles; shellfish; vaccination; Vaccination - veterinary; Vaccines; Vaccines, Inactivated - administration & dosage; Vaccines, Inactivated - immunology; Vibrio - immunology; Vibrio harveyi; Vibrio Infections - immunology; Vibrio Infections - prevention & control; Vibrio Infections - veterinary; Vibriosis
• ISSN: 1050-4648; 1095-9947; 1095-9947
• DOI: 10.1016/j.fsi.2024.109557

Immersion vaccination, albeit easier to administer than immunization by injection, sometimes has challenges with antigen uptake, resulting in sub-optimal protection. In this research, a new strategy to enhance antigen uptake of a heat-inactivated Vibrio harveyi vaccine in Asian seabass (Lates calcarifer) using oxygen nanobubble-enriched water (ONB) and positively charged chitosan (CS) was explored. Antigen uptake in fish gills was assessed, as was the antibody response and vaccine efficacy of four different combinations of vaccine with ONB and CS, and two control groups. Pre-mixing of ONB and CS before introducing the vaccine, referred to as (ONB + CS) + Vac, resulted in superior antigen uptake and anti-V. harveyi antibody (IgM) production in both serum and mucus compared to other formulas. The integration of an oral booster (4.22 × 108 CFU/g, at day 21–25) within a vaccine trial experiment set out to further evaluate how survival rates post exposure to V. harveyi might be improved. Antibody responses were measured over 42 days, and vaccine efficacy was assessed through an experimental challenge with V. harveyi. The expression of immune-related genes IL1β, TNFα, CD4, CD8, IgT and antibody levels were assessed at 1, 3, and 7-day(s) post challenge (dpc). The results revealed that antibody levels in the group (ONB + CS) + Vac were consistently higher than the other groups post immersion immunization and oral booster, along with elevated expression of immune-related genes after challenge with V. harveyi. Ultimately, this group demonstrated a significantly higher relative percent survival (RPS) of 63 % ± 10.5 %, showcasing the potential of the ONB-CS-Vac complex as a promising immersion vaccination strategy for enhancing antigen uptake, stimulating immunological responses, and improving survival of Asian seabass against vibriosis. •The (ONB + CS) + Vac complex altered the charge of the inactivated V. harveyi vaccine from negative to positive.•This formulation notably enhanced vaccine uptake, leading to superior systemic and mucosal antibody responses in comparison to other groups.•Single immersion resulted in short-lived antibody persistence.•Immersion priming followed by oral booster vaccination resulted in robust immunity and effective protection.•This vaccination approach sets the stage for developing user-friendly, non-invasive vaccines in aquaculture.