Figure 4

Sera of BALB/c mice immunized with bioconjugate shows a directed IgG immune response against N-formylperosamine of Y. enterocolitica O:9 and Brucella spp. A) Control sera and B) Immune sera raised by injecting purified glycoproteins containing 3 μg glycan: 1) Unglycosylated AcrA, 2) HP-, 3) OC-, 4) WT. Both sets of sera react with each glycoprotein due to the high immunostimulatory characteristic of AcrA. C) Control sera and D); immune serum (IgG response) blotted against Y. enterocolitica 0:9 LPS from different strains from Figure 1. 5) OC-/HP-, 6) HP-, 7) OC-, 8) WT. Only the test serum was reactive against the higher molecular weight portion corresponding to the homopolymer of N-formylperosamine. E) Control sera and F) immune serum blotted against Brucella spp. LPSs: 9) B. abortus, 10) B. melitensis, and 11) B. suis. Only the immune sera are reactive against the Brucella LPS. Interestingly, although each LPS is comprised of N-formylperosamine, different linkages are present which may cause the difference in reactivity of the sera.