Development of a Plant-Expressed Subunit Vaccine against Brucellosis

Area of Science:

• Vaccinology
• Plant biotechnology
• Immunology

Background:

• Brucellosis is a significant zoonotic disease with current vaccines posing safety risks.
• Existing Brucella vaccines are effective but cause animal abortions and are pathogenic to humans.
• Virus-like particles (VLPs) offer a promising scaffold for presenting antigens to the immune system.

Purpose of the Study:

• To develop a novel, safe, and effective subunit vaccine against Brucellosis.
• To present Brucella melitensis T cell epitopes on Orbivirus core-like particles (CLPs).
• To express chimeric CLPs in Nicotiana benthamiana plants for potential vaccine production.

Main Methods:

• Selected Brucella melitensis T cell epitopes were engineered onto Orbivirus core-like particles (CLPs).
• Chimeric CLPs were transiently expressed in Nicotiana benthamiana plants.
• Safety and efficacy of plant-expressed chimeric CLPs were evaluated in a mouse model of brucellosis.

Main Results:

• Five distinct chimeric CLPs, each displaying a unique T cell epitope, were successfully assembled in N. benthamiana.
• Three high-yield chimeric CLPs were tested and found to be safe in BALB/c mice.
• One chimeric CLP conferred protection against virulent Brucella challenge, comparable to the commercial Rev1 vaccine.

Conclusions:

• Plant-expressed chimeric CLPs displaying Brucella melitensis T cell epitopes can be successfully assembled.
• The developed chimeric CLPs are safe for inoculation in a mouse model.
• This study represents a crucial first step towards a safe and effective plant-based subunit vaccine for Brucellosis.