New synthesis of oligosaccharides modelling the M epitope of the Brucella O-polysaccharide.

Brucellosis is a dangerous zoonotic disease caused by bacteria of the genus Brucella. Diagnosis of brucellosis is based on the detection in animal and human sera of antibodies to the O-polysaccharide of Brucella lipopolysaccharide. The currently employed serodiagnosis of brucellosis relies on the use of the Brucella O-polysaccharide as a diagnostic antigen. However, the existence of bacterial species, which also express O-polysaccharides structurally similar to that of Brucella, may decrease the specificity of the brucellosis detection due to false-positive test results. It has been shown that the efficiency of the test can be significantly improved by using synthetic oligosaccharides that correspond to the so-called M epitope of the Brucella O-antigen. This epitope is characterized by an α-(1→3)-linkage between d-perosamine units and is unique to Brucella. Here we report on an efficient approach to the synthesis of oligosaccharides that model the M epitope of the Brucella O-polysaccharide. The approach is based on the use of the α-(1→3)-linked disaccharide thioglycoside as the key donor block. Its application allowed the straightforward assembly of a set of four protected oligosaccharides, which includes a disaccharide, two trisaccharides, and a tetrasaccharide, in five glycosylation steps. The synthesized oligosaccharides are planned to be used in the development of diagnostic tools for identifying brucellosis in humans and domestic animals, as well as a potential vaccine against it.

Russian collection of Brucella abortus vaccine strains: annotation, implementation and genomic analysis.

Over the past 10 years, immunization of cattle in Russia has been performed using vaccines from Brucella abortus strains 82, 19 and 75/79. To prevent brucellosis in small ruminants, two vaccines have been used, from the Brucella melitensis strain REV-1 and the B. abortus strain 19; note that twice as many animals have been immunized with the former vaccine than with the latter vaccine. The disadvantage of using these preparations is the formation of prolonged post-vaccination seropositivity, which is especially pronounced in animals after immunization with vaccines from B. abortus strain 19 and B. melitensis strain REV-1. This study aims to perform the whole genome sequencing of Brucella vaccine strains from the Russian collection. A bioinformatics analysis of the genomic data proved that the vaccine strains 75/79AB, 82, R-1096, and the KV 17/100 belong to ST-2, 104 M to ST-1, KV 13/100 to ST-5. This analysis allowed us to characterize vaccine strains's phylogenetic relationships and to prove the close relation of vaccine strains 75/79AB, 82, R-1096. Also, we defined candidate mutations in genes pmm, wbdA, wbkA, wboA, and eryB, which could be responsible for the attenuated virulence of vaccine strains. The complete genomic sequences of B. abortus strains make further studies of bacterial pathogenicity determinants and virulence phenotype feasible, as well as their use in quality control of animal medicines.

Targeted prevention of brucellosis in cattle, sheep, and goats in the Russian Federation.

The article presents a brief history of the brucellosis prevention in animals in the world and in the Russian Federation. Data are taken from studies on the immunogenic activity and epizootic efficacy of vaccines against brucellosis in animals, which made it possible, in the final analysis, to regard these preparations as highly important for brucellosis prevention. The relationship between the epizootic brucellosis situation in Russia and the employment of specific agents in targeted prevention of brucellosis in cattle, sheep, and goats, and the sequence of their use, are presented briefly, substantiating the feasibility of their use and improvement.

Designing vaccines against cattle brucellosis.

The article presents the results from a study of two new vaccines against cattle brucellosis from Brucella abortus cultures. One of these is a live dry vaccine prepared from a weakly agglutinogenic strain in the SR form and the second, an inactivated adjuvant vaccine from an non-agglutinogenic strain in the R form. The immunogenic properties of the vaccines were studied in three tests on heifers with infection by a virulent B. abortus culture. The vaccines passed the farm-scale testing and were accepted in veterinary practice.

Development and characterization of a modified Komarov's bullet for ballistic delivery of live Brucella abortus strains 82 and 19 to cattle and bison.

In this study a modified Komarov's bullet was developed to remotely deliver live brucellosis vaccines (Brucella abortus 82 and Brucella abortus 19). After modification, the bullet payload could carry the desired dose (10(11)CFU) of vaccine. As the bullet components were toxic to the live bacteria, a special protective coating was developed for the bullet inner surface that maintained vaccine viability. Vaccine viability was not influenced by ballistic delivery and the characteristics of the modified bullet allowed accurate delivery at distances of 100m. Intramuscular ballistic delivery of the modified Komarov's bullet into live cattle and bison was not associated with detrimental clinical effects. The modified bullet penetrated approximately 3-5.5cm into muscular tissue. At necropsy after 63 days, recovered bullets were deformed or broken into multiple pieces but were not associated with adverse lesions. Ballistically delivered vaccines of both strains induced high immunological responses in cattle and bison confirmed by serological, immunological tests, PCR and pathomorphological examination of internal organs. Therefore, the clinical and ballistic characteristics of the modified Komarov's bullet, in addition to its ability to be delivered at distances of 100m, demonstrate its usefulness for use in remotely delivering brucellosis vaccines to free-ranging animals. A high immune response induced by ballistically delivered Brucella abortus 82 vaccine proves that this vaccine strain can be used for vaccination of free-ranging animals.