Vaccination with recombinant L7/L12-truncated Omp31 protein induces protection against Brucella infection in BALB/c
Maryam Golshani1, Sima Rafati2, Amir Dashti1
1Department of Molecular Biology, Pasteur Institute of Iran, Pasteur Street, Tehran, Iran.
Abstract:
Brucellosis is the most common bacterial zoonotic disease worldwide and no vaccine is available for the prevention of human brucellosis. In humans, brucellosis is mostly caused by Brucella melitensis and Brucella abortus. The Outer membrane protein 31 (Omp31) and L7/L12 are immunodominant and protective antigens conserved in human Brucella pathogens. In the present study, we evaluated the humoral and cellular immune responses induced by a fusion protein designed based on the Truncated form of Omp31 (TOmp31) and L7-L12 antigens. Vaccination of BALB/c mice with the recombinant fusion protein (rL7/L12-TOmp31) provided the significant protection level against B. melitensis and B. abortus challenge. Moreover, rL7/L12-TOmp31 elicited a strong specific IgG response (higher IgG2a titers) and significant IFN-γ/IL2 production and T-cell proliferation was also observed. The T helper1 (Th1) oriented response persisted for 12 weeks after the first immunization. The rL7/L12-TOmp31 could be a new potential antigen candidate for the development of a subunit vaccine against B. melitensis and B. abortus.
Insights
A new fusion protein, rL7/L12-TOmp31, shows promise as a subunit vaccine against Brucellosis. This vaccine candidate induced significant protection and a robust immune response in mice against Brucella melitensis and Brucella abortus.
Area of Science:
- Immunology
- Vaccinology
- Microbiology
Background:
- Brucellosis is a prevalent bacterial zoonotic disease globally, with no existing human vaccine.
- Brucella melitensis and Brucella abortus are the primary human pathogens responsible for brucellosis.
- Outer membrane protein 31 (Omp31) and L7/L12 are identified as key protective antigens in Brucella.
Purpose of the Study:
- To assess the immune responses and protective efficacy of a novel fusion protein combining truncated Omp31 (TOmp31) and L7-L12 antigens.
- To evaluate the potential of the recombinant fusion protein (rL7/L12-TOmp31) as a subunit vaccine candidate against human brucellosis.
Main Methods:
- Development of a recombinant fusion protein (rL7/L12-TOmp31) using TOmp31 and L7-L12 antigens.
- Vaccination of BALB/c mice with rL7/L12-TOmp31.
- Challenge experiments with Brucella melitensis and Brucella abortus.
- Analysis of humoral (IgG titers) and cellular (IFN-γ, IL-2, T-cell proliferation) immune responses.
Main Results:
- rL7/L12-TOmp31 vaccination conferred significant protection against B. melitensis and B. abortus challenge in mice.
- The fusion protein induced a strong specific IgG response, notably higher IgG2a titers.
- Significant production of IFN-γ and IL-2, along with notable T-cell proliferation, was observed.
- A persistent T helper1 (Th1) oriented immune response was maintained for 12 weeks post-initial immunization.
Conclusions:
- The recombinant fusion protein rL7/L12-TOmp31 demonstrates significant potential as a subunit vaccine candidate.
- This antigen elicits a protective immune response against key Brucella species.
- Further development of rL7/L12-TOmp31 could lead to a novel vaccine for human brucellosis prevention.
