Influenza viral vectors expressing the Brucella OMP16 or L7/L12 proteins as vaccines against B. abortus infection.
BACKGROUND
We generated novel, effective candidate vaccine against Brucella abortus based on recombinant influenza viruses expressing the Brucella ribosomal protein L7/L12 or outer membrane protein (Omp)-16 from the NS1 open reading frame. The main purpose of this work was to evaluate the safety, immunogenicity and protectiveness of vaccine candidate in laboratory animals.


RESULTS
Four recombinant influenza A viral constructs of the subtypes Н5N1 or H1N1 expressing the Brucella proteins L7/L12 or Omp16 were obtained by a reverse genetics method: Flu-NS1-124-L7/L12-H5N1, Flu-NS1-124-Omp16-H5N1, Flu-NS1-124-L7/L12-H1N1 and Flu-NS1-124-Omp16-H1N1. Despite of substantial modification of NS1 gene, all constructs replicated well and were retain their Brucella inserts over five passages in embryonated chicken eggs (CE). Administration of the mono- or bivalent vaccine formulation via prime-boost intranasal (i.n.), conjunctival (c.) or subcutaneous (s.c.) immunization was safe in mice; no deaths, body weight loss or pathomorphological changes were observed over 56 days. Moreover, guinea pigs vaccinated i.n. with vaccine vectors did not shed the vaccine viruses through their upper respiratory tract after the prime and booster vaccination. These findings confirmed the replication-deficient phenotype of viral vectors. The highest antibody response to Brucella antigen was obtained with constructs expressing L7/L12 (ELISA, GMT 242.5-735.0); whereas the highest T-cell immune response- with construct expressing Omp16 (ELISPOT, 337 ± 52-651 ± 45 spots/4×105cells), which was comparable (P > 0.05) to the response induced by the commercial vaccine B. abortus 19. Interestingly, c. immunization appeared to be optimal for eliciting T-cell immune response. In guinea pigs, the highest protective efficacy after challenge with B. abortus 544 was achieved with Omp16 expressing constructs in both monovalent or bivalent vaccine formulations; protective efficacy was comparable to those induced by a commercial live B. abortus 19 vaccine.


CONCLUSIONS
Thus, influenza vectors expressing Brucella protective antigens can be developed as novel influenza vectored vaccine against B. abortus infection.
The Research Institute for Biological Safety Problems, Zhambulskaya oblast, Kordaiskiy rayon, Gvardeisky, Republic of Kazakhstan. tabynov_81@mail.ru.
Kaissar
K
Tabynov
Abylai
A
Sansyzbay
Zhailaubay
Z
Kydyrbayev
Bolat
B
Yespembetov
Sholpan
S
Ryskeldinova
Nadezhda
N
Zinina
Nurika
N
Assanzhanova
Kulaisan
K
Sultankulova
Nurlan
N
Sandybayev
Berik
B
Khairullin
Irina
I
Kuznetsova
Boris
B
Ferko
Andrej
A
Egorov
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D002004:Brucella Vaccine / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D002003:Brucella abortus / Q000235:genetics / Q000276:immunology*; D002006:Brucellosis / Q000276:immunology / Q000517:prevention & control*; D004195:Disease Models, Animal; D004337:Drug Carriers; D005822:Genetic Vectors; D042822:Genomic Instability; D006168:Guinea Pigs; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics*; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics*; D051379:Mice; D012269:Ribosomal Proteins / Q000235:genetics / Q000276:immunology; D016019:Survival Analysis; D013601:T-Lymphocytes / Q000276:immunology; D014611:Vaccination / Q000379:methods; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014779:Virus Replication
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002004:Brucella Vaccine; D004337:Drug Carriers; D012269:Ribosomal Proteins; D014614:Vaccines, Synthetic; C016700:ribosomal protein L7-L12