Evaluation of comparative effect between aluminum hydroxide gel and montanide (ISA 70) in potency and protection of locally prepared rabbit hemorrhagic disease virus 2 (RHDV2) vaccines in rabbits

• Published in: BMC veterinary research Vol. 20; no. 1; pp. 407 - 8
• Main Authors: Ahmed, Doha Abd Alrahman, Sadiek, Yasmin, Eldin, Mostafa Saif, Ibrahim, Ragab S, Amen, Omar, Abodalal, Samah El Sayed Ali
• Format: Journal Article
• Language: English
• Published: England BioMed Central 11-09-2024; BMC
• Subjects: Adjuvants, Immunologic - administration & dosage; Adjuvants, Immunologic - pharmacology; Aluminum Hydroxide - administration & dosage; Aluminum Hydroxide - pharmacology; Animals; Caliciviridae Infections - prevention & control; Caliciviridae Infections - veterinary; Gels; Hemorrhagic Disease Virus, Rabbit - immunology; Humoral immune response; Montanide ISA70; Oleic Acids - administration & dosage; Oleic Acids - pharmacology; Potency; Rabbits; RHDV2; Vaccination; Vaccines, Inactivated - immunology; Viral Vaccines - immunology; Humoral immune response; Potency; Montanide ISA70; Vaccination; RHDV2
• ISSN: 1746-6148; 1746-6148
• DOI: 10.1186/s12917-024-04239-w

Rabbit hemorrhagic disease (RHD) is an acute infectious disease that damages the rabbit industry by producing significant mortality rates in young and adult rabbits. RHD is better controlled by vaccination.
The current study's goal was to prepare and evaluate the immuno-enhancing effect of montanide ISA70 and aluminum hydroxide (Al(OH)
) gel incorporated within the inactivated RHDV2 vaccine and assess the vaccine's protective efficacy against the homologous and heterologous local RHDV2 strains in rabbits.
Inactivated RHDV vaccines were prepared using Montanide ISA70 oil or Al(OH)
gel adjuvants and submitted to sterility, safety, and potency tests. 200 rabbits were equally divided into 4 groups: G1 (control), G2 (vaccinated with gel-incorporated vaccine), G3 (vaccinated with montanide-incorporated vaccine), and G4 (vaccinated with gel- and montanide-incorporated vaccines). Individual blood samples were collected from one week to six months from all groups. The vaccine's potency was measured by the HI test and protection percentage post challenge.
Data revealed slightly increasing HI titer means reaching the 1st peak at 4 weeks post-vaccination (7.33, 7.67, and 7.33 log2 in the 2nd, 3rd, and 4th groups, respectively), then slightly decreasing and peaked again, giving 9.33 log2 for the2
group at 3 months post-vaccination (MPV), 10.67 log2 for 3rd the group, and 10.33 log2 for the 4th group at 5 months post-vaccination. Titer gradually decreased but remained protective. The protection rate ranged from 80-100% and 80-90% for homologous and heterologous local RHDV2 vaccines, respectively, within 3 weeks and 6 months post-challenge. The montanide oil RHDV2 vaccine induced better protection than the aluminum gel RHDV2 vaccine.
The results demonstrated evidence of cross-protection between RHDV2 strains. The oil emulsion vaccine induced higher and longer-lasting antibody titers than those obtained with the RHDV2 aluminum gel vaccine.