TABLE 6.

Immunization of mice with N. lactamica OMVs or <43-kDa protein pool protects against intraperitoneal challenge with N. meningitidis K454a

Challenge dose (CFU) of N. meningitidis K454VaccineNo. of survivors (no. healthy)No. of survivors/ no. in group at 72 h
24 h52 h
4.4 × 106None000/20
OMVs20 (20)20 (20)20/20
<43-kDa pool19 (11)14 (14)14/20
8.7 × 107None1 (0)0 (0)0/20
OMVs15 (1)5 (3)3/20
<43-kDa pool8 (1)2 (2)2/20
  • a Both the OMVs and <43-kDa protein pool were prepared with Alhydrogel as the adjuvant. At the lower dose at 24 h postinfection (the time of the last death in the unvaccinated group), protection was significant for both vaccines compared with the unvaccinated group (P <0.001, chi-square test with Yates' correction); in addition, there was a significant difference between the number of survivors in the group vaccinated with the <43-kDa protein pool compared with the OMV vaccine (P < 0.05).