Development and trial of vaccines againstBrucella

Abstract

The search for ideal brucellosis vaccines remains active today. Currently, no licensed human or canine anti-brucellosis vaccines are available. In bovines, the most successful vaccine (S19) is only used in calves, as adult vaccination results in orchitis in male, prolonged infection, and possible abortion complications in pregnant female cattle. Another widely deployed vaccine (RB51) has a low protective efficacy. An ideal vaccine should exhibit a safe profile as well as enhance protective efficacy. However, currently available vaccines exhibit one or more major drawbacks. Smooth live attenuated vaccines suffer shortcomings such as residual virulence and serodiagnostic interference. Inactivated vaccines, in general, confer relatively low levels of protection. Recent developments to improve brucellosis vaccines include generation of knockout mutants by targeting genes involved in metabolism, virulence, and the lipopolysaccharide synthesis pathway, as well as generation of DNA vaccines, mucosal vaccines, and live vectored vaccines, have all produced varying degrees of success. Herein, we briefly review the bacteriology, pathogenesis, immunological implications, candidate vaccines, vaccinations, and models related to Brucella.

Brucella ovis mutant in ABC transporter protects against Brucella canis infection in mice and it is safe for dogs

“…Here we demonstrated that the vaccine strain BoΔabcBA did not cause lesions or disease in immunized dogs, which is smilar to previous findings in mice [20] and rams [22] in which this strain also did not cause lesions. Commercial vaccines against bovine brucellosis are usually administered to young and non-pregnant females, because these vaccine strains possesses residual virulence and can cause abortion in pregnant females [37] or orchitis and epididymitis in males [41]. In contrast, BoΔabcBA did not induce any clinical change in both male and female immunized dogs.…”

Research Article DNA vaccine and DNA prime-protein boost with the <i>virB9</i> and <i>virB12</i> genes induced low level of protection against <i>Brucella</i> <i>abortus</i> infection in mice

“…In our study, the DNA vaccine enhanced by the recombinant protein booster induced a specific humoral immune response against rVIRB9 and rVIRB12, but it offered low protection for the mice against infection. Specific antibodies are important in reducing the initial phase of a Brucella infection, but a strong humoral immunity unaccompanied by cell-mediated immunity (CMI) cannot provide total protection against the Brucella organism (Lalsiamthara and Lee, 2017). In some situations, inoculation with "naked" plasmid DNA has been shown to not produce an immune response as strong as either purified protein or even a commercial Brucella vaccine (Cassataro et al, 2007;Golshani et al, 2015).…”

“…The ability of live vaccines, such as S19, in controlling infections is most likely a direct effect of the capacity of the bacteria to infect the host cell, and to allow the immune system access to a variety of antigens that jointly contribute to a stronger and more extensive response. However, this vaccine induces abortions in pregnant animals and is virulent for humans; moreover, it elicits anti-Brucella antibodies that interfere with serodiagnosis (Lalsiamthara and Lee, 2017).…”

“…Subunit vaccines, including DNA vaccines and recombinant proteins, present similar characteristics and advantages over the live S19 vaccine such as: being highly safe; no residual virulence; and provide the strategy known as differentiated infected from vaccinated animals (DIVA) (Lalsiamthara and Lee, 2017). There are however, some disadvantages which include poor immunogenicity when used alone, and also the requirement of adjuvants to elicit a protective and long-lasting immune response.…”

A novel, rapid and simple method for detecting brucellosis based on rapid vertical flow technology

“…Animals infected with brucellosis show symptoms of chronic infection, which has a direct economic impact via reduced fertility, increases in abortion, reductions in weight and a substantial decline in milk production (Khan and Zahoor ). Several live vaccines have been developed and are used in certain countries, but they have not been widely adopted (Lalsiamthara and Lee ).…”