Responses of cattle to two dosages ofBrucella abortusstrain RB51: serology, clearance and efficacy

Olsen, Steven C.; Bricker, Betsy J.; Palmer, Mitchell V.; Jensen, Allen E.; Cheville, N. F.

doi:10.1053/rvsc.1998.0251

Cited by 48 publications

(47 citation statements)

References 11 publications

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“…As expected, 100% of the cattle subcutaneously vaccinated with RB51 develop antibodies to R antigens that can be detected in a dot ELISA and other tests [89,91,93,95,119]. On the contrary, vaccination with RB51 does not significantly interfere in classical tests such as the rose bengal, tube agglutination and the complement fixation test [21,22,45,95,[117][118][119]137].…”

Section: Interference In S-lps Testsmentioning

confidence: 74%

Rough vaccines in animal brucellosis: Structural and genetic basis and present status

Grilló²,

et al. 2004

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-Brucellosis control and eradication requires serological tests and vaccines. Effective classical vaccines (S19 in cattle and Rev 1 in small ruminants), however, induce antibodies to the O-polysaccharide of the lipopolysaccharide which may be difficult to distinguish from those resulting from infection and may thus complicate diagnosis. Rough attenuated mutants lack the O-polysaccharide and would solve this problem if eliciting protective immunity; the empirically obtained rough mutants 45/20 and RB51 have been used as vaccines. Strain 45/20 is reportedly unstable and it is not presently used. RB51 is increasingly used instead of S19 in some countries but it is rifampicin resistant and its effectiveness is controversial. Some controlled experiments have found good or absolute protection in adult cattle vaccinated orally (full dose) or subcutaneously (reduced dose) and in one field experiment, RB51 was reported to afford absolute protection to calves and to perform better than S19. Controlled experiments in calves, however, have shown reduced doses of RB51 to be ineffective, full doses only partially effective, and RB51 less effective than S19 against severe challenges. Moreover, other observations suggest that RB51 is ineffective when prevalence is high. RB51 is not useful in sheep and evidence in goats is preliminary and contradictory. Rough mutants obtained by molecular biology methods on the knowledge of the genetics and structure of Brucella lipopolysaccharide may offer alternatives. The B. abortus manB core (rfbK) mutant seems promising in cattle, and analyses in mice suggest that mutations affecting only the O-polysaccharide result in better vaccines than those affecting both core and O-polysaccharide. Possible uses of rough vaccines also include boosting immunity by revaccination but solid evidence on its effectiveness, safety and practicality is not available.

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Section: Interference In S-lps Testsmentioning

confidence: 74%

Rough vaccines in animal brucellosis: Structural and genetic basis and present status

Grilló²,

et al. 2004

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“…This strain, a rough rifampin-resistant B. abortus mutant derived from virulent B. abortus strain 2308, shows negligible interference with serological diagnosis and induces protective immunity in cattle similar to that afforded by B. abortus S19 (9,34,43). Data obtained using mice showed that RB51 is able to protect against infections with heterologous Brucella strains, including B. melitensis, B. ovis, B. abortus, and B. suis (19).…”

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confidence: 99%

Protective Properties of Rifampin-Resistant Rough Mutants ofBrucella melitensis

et al. 2005

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Vaccination against Brucella infections in animals is usually performed by administration of live attenuated smooth B. abortus strain S19 and B. melitensis strain Rev1. They are proven effective vaccines against B. abortus in cattle and against B. melitensis and B. ovis in sheep and goats, respectively. However, both vaccines have the main drawback of inducing O-polysaccharide-specific antibodies that interfere with serologic diagnosis of disease. In addition, they retain residual virulence, being a cause of abortion in pregnant animals and infection in humans. To overcome these problems, one approach is to develop defined rough mutant Brucella strains lacking O antigen of lipopolysaccharide. B. abortus rough strain RB51, a rifampin-resistant mutant of virulent strain B. abortus 2308, is used as a vaccine against B. abortus infection in cattle in some countries. However, RB51 is not effective in sheep, and there is only preliminary evidence that it is effective in goats. In this study, we tested the efficacies of six rifampin-resistant rough strains of B. melitensis in protecting BALB/c mice exposed to B. melitensis infection. The protective properties, as well as both humoral and cellular immune responses, were assessed in comparison with those provided by B. melitensis Rev1 and B. abortus RB51 vaccines. The results indicated that these rough mutants were able to induce a very good level of protection against B. melitensis infection, similar to that provided by Rev1 and superior to that of RB51, without inducing antibodies to O antigen. In addition, all B. melitensis mutants were able to stimulate good production of gamma interferon. The characteristics of these strains encourage further evaluation of them as alternative vaccines to Rev1 in primary host species.Brucellosis is a major zoonotic disease, widely distributed in humans and domestic and wild animals, especially in developing countries. Among the different species of the Brucella genus, B. abortus and B. melitensis are the most pathogenic and virulent, not only for cattle or for sheep and goats, respectively, but also for other animal species. The occurrence of the disease in humans is largely dependent on the animal reservoir, with the highest rate of human infection in areas where rates of brucellosis in sheep and goats are high (6,35).Brucellosis vaccines are essential elements in control programs. Attenuated B. abortus strain 19 and B. melitensis strain Rev1 are proven effective vaccines; they induce good levels of protection against B. abortus in cattle and against B. melitensis in sheep and goats, preventing premature abortions (7, 30, 31). However, both vaccines have the drawback of inducing Opolysaccharide-specific antibodies that interfere with the discrimination between vaccinated and infected animals during serological screening (7, 31). In addition, they retain pathogenicity and sometimes cause abortion in vaccinated animals (10, 18, 41) and remain infectious for humans (3,5,26). The use of the conjunctival route when administering B. melit...

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“…This variant, designated B. abortus RB51 is currently being used in many countries as an alternative vaccine to B. abortus S19 because it does not induce antibodies to Brucella lipopolysaccharide Oantigens (17)(18)(19)(20)(21). At the same time, B. abortus RB51 retains the ability to confer protection against infection with pathogenic strains (5,7,10,12). B. abortus RB51 can persist for a short period of time in the spleens of mice vaccinated by intraperitoneal injection.…”

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confidence: 99%

Brucella abortusRB51 Induces Protection in Mice Orally Infected with the Virulent StrainB. abortus2308

et al. 2003

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Brucellae are gram-negative, facultative intracellular bacteria which are one of the most common causes of abortion in animals. In addition, they are the source of a severe zoonosis. In this trial, we evaluated the effect of oral inoculation of Brucella abortus RB51 in mice against a challenge infection with B. abortus 2308. First, we showed that a gastric acid neutralization prior to the oral inoculation contributed to a more homogeneous and consistent infection with both vaccine strain B. abortus RB51 and virulent strain B. abortus 2308. Successively, we assessed the clearance and the immune response following an oral infection with B. abortus RB51. Oral inoculation gave a mild infection which was cleared 42 days after infection, and it induced a delayed humoral and cell-mediated immune response. Finally, we immunized mice by oral inoculation with B. abortus RB51, and we challenged them with the virulent strain B. abortus 2308 by an oral or intraperitoneal route 42 days after vaccination. Oral inoculation of B. abortus RB51 was able to give protection to mice infected with the virulent strain B. abortus 2308 by the oral route but not to mice infected intraperitoneally. Our results indicate that oral inoculation of mice with B. abortus RB51 is able to give a protective immunity against an oral infection with virulent strains, and this protection seems to rely on an immune response at the mucosal level.Brucellae are gram-negative, facultative intracellular bacteria which are one of the most common causes of abortion in animals. In addition, they are the source of a severe zoonosis, which is characterized in human beings by a multitude of somatic complaints, including fever, sweats, anorexia, fatigue, malaise, weight loss, and depression (15). Immune response to Brucella spp. have been studied mainly with mice. In this animal model, protective immunity seems to be mediated by both humoral and cellular immune responses (2). In particular, in vivo studies indicate that an immune response mediated by both CD4 ϩ and CD8 ϩ T lymphocytes is important in controlling infection. Within these subsets, gamma interferon-producing CD4 ϩ T cells play a prominent role in recovery from infection (23). Vaccination against Brucella infections in animals is usually performed by parenteral administration of live attenuated smooth Brucella abortus S19. This vaccine is effective in conferring protection against virulent strains of B. abortus, but it also has a number of disadvantages, including causing abortion in pregnant animals, being pathogenic for humans, and inducing a humoral response which is similar to the response after natural infection, thus hampering procedures for the detection of infected animals by serological testing. In particular, the similarity in humoral responses is of great importance in field conditions because it is impossible, with B. abortus as the antigen, to serologically discriminate between vaccinated and infected animals (11). Recently, a stable, lipopolysaccharide O-antigen-deficient mutant of virulent...

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Responses of cattle to two dosages ofBrucella abortusstrain RB51: serology, clearance and efficacy

Cited by 48 publications

References 11 publications

Rough vaccines in animal brucellosis: Structural and genetic basis and present status

Rough vaccines in animal brucellosis: Structural and genetic basis and present status

Protective Properties of Rifampin-Resistant Rough Mutants ofBrucella melitensis

Brucella abortusRB51 Induces Protection in Mice Orally Infected with the Virulent StrainB. abortus2308

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