Immunization with the Recombinant Cholera Toxin B Fused to Fimbria 2 Protein Protects against Bordetella pertussis Infection

Abstract EN

This study examined the immunogenic properties of the fusion protein fimbria 2 of Bordetella pertussis (Fim2)—cholera toxin B subunit (CTB) in the intranasal murine model of infection.

To this end B.

pertussis Fim2 coding sequence was cloned downstream of the cholera toxin B subunit coding sequence.

The expression and assembly of the fusion protein into pentameric structures (CTB-Fim2) were evaluated by SDS-PAGE and monosialotetrahexosylgaglioside (GM1-ganglioside) enzyme-linked immunosorbent assay (ELISA).

To evaluate the protective capacity of CTB-Fim2, an intraperitoneal or intranasal mouse immunization schedule was performed with 50 μg of CTB-Fim2.

Recombinant (rFim2) or purified (BpFim2) Fim2, CTB, and phosphate-buffered saline (PBS) were used as controls.

The results showed that mice immunized with BpFim2 or CTB-Fim2 intraperitoneally or intranasally presented a significant reduction in bacterial lung counts compared to control groups (P<0.01 or P<0.001, resp.).

Moreover, intranasal immunization with CTB-Fim2 induced significant levels of Fim2-specific IgG in serum and bronchoalveolar lavage (BAL) and Fim2-specific IgA in BAL.

Analysis of IgG isotypes and cytokines mRNA levels showed that CTB-Fim2 results in a mixed Th1/Th2 (T-helper) response.

The data presented here provide support for CTB-Fim2 as a promising recombinant antigen against Bordetella pertussis infection.