A deep rough type structure in Bordetella bronchiseptica lipopolysaccharide modulates host immune responses

SISTI, FEDERICO; FERNANDEZ, JULIETA; HIGGINS SC; CASABUONO, ADRIANA; COUTO ALICIA; MILLS KH; HOZBOR, DANIELA

MICROBIOLOGY AND IMMUNOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 55 p. 847 - 858

0385-5600

We have already obtained the Bordetella bronchiseptica mutant BbLP39, which contains a deep-rough lipopolysaccharide (LPS) instead the wild type smooth LPS with O antigen. This mutant was altered in the expression of some proteins and in its ability to colonize mice lungs. Particularly, in BbLP39 the expression of pertactin is decreased. To differentiate the contribution of each bacterial component to the observed phenotype, here we used mice defective in the LPS sensing receptor TLR4 (TLR4-defective mice). In contrast to wild-type mice, infection of TLR4-defective mice with BbLP39 resulted in lung infection, which persisted for more than 10 days post-challenge. Comparative analysis of the immune responses induced by purified mutant and wild type LPSs showed that the mutant LPS induced significantly higher TNF-α and IL-10 mRNA expression levels than the wild type. UV MALDI TOF mass spectrometry analysis revealed that both LPSs had the same penta-acylated lipid A structure. However, the lipid A from BbLP39 contained pyrophosphate instead of phosphate at position 1. This structural difference, in addition to the lack of O-antigen in BbLP39, may explain the functional differences between BbLP39 and wild type strains.