Protecting mice from fatal Bordetella bronchiseptica infection by immunization with recombinant pertactin antigens

Abstract:

[Objective] We evaluated the efficacy of the recombinant pertactin (PRN)-specific active or passive immunization against Bordetella bronchiseptica (Bb) in an aerosol challenge model established by using BALB/c mice. [Methods and results] Mice, immunized subcutaneously with two doses of purified glutathione S-transferase (GST)-PRN protein mixed with an equal volume of Freund’s adjuvant, produced robust PRN-specific IgG antibody activity. All 20 mice vaccinated with GST-PRN protein survived aerosol challenge with three times the 50% lethal dose (LD50) of virulent Bb HH0809 compared with 3 of 20 GST protein-treated controls and 4 of 20 PBS-treated controls that survived. Furthermore, we observed complete protection against intraperitoneal challenge with ten times the LD50 of virulent HH0809 strain in mice that were injected intraperitoneally with 0.5 ml rabbit anti-GST-PRN serum. No survivors were observed in mice that received either rabbit anti-GST serum or PBS alone. [Conclusion] The recombinant PRN protein had strong immuno-genicity against Bb infection.