Tn5-induced lipopolysaccharide mutations in Bordetella pertussis that affect outer membrane function

Abstract

An LPSB-specific mAb was used to screen for ten TnS insertion mutants of Bordetella pertussis which have LPS which is phenotypically distinct from either wild-type LPSAB or LPSB. Silver-stained SDS-PAGE gels showed nine different LPS phenotypes, six of which contain two clinically undocumented LPS bands, designated lntA and lntB based on their proximity to the LPSA and LPSB bands, respectively. Binding assays with LPSA-and LPSB-specif ic mAbs established changes in epitope exposure for the various mutant LPS, both in cell-free form and as presented on the surface of whole cells. The possible involvement of a number of genes, both structural and regulatory, was indicated in production of the altered phenotypes. PFGE and Southern blotting showed that the TnS inserts of seven mutants mapped to a region of the B. pertussis chromosome shown previously to encode the bpl gene products of LPS biosynthesis. Mutants MLT3, MLT5 and MLT8, however, mapped to distinctly different parts of the chromosome. In addition, mutants MLT2 and MLT3 contributed to an accelerated frequency in the appearance of avirulent phase organisms despite their TnS inserts being over 1000 bp from the bvglASR locus. The alterations in LPS structure in the mutants changed their reactivity to strain-specific mAbs and their sensitivity to hydrophobic and hydrophil ic antibiotics.

Bordetella pertussis Lipopolysaccharide Resists the Bactericidal Effects of Pulmonary Surfactant Protein A

“…A number of mutations have been introduced into this operon, leading to the generation of mutant strains lacking one, two, or all three of the terminal sugars. WlbH lacks the terminal sugar (17,18), MLT7 appears to lack the last two sugars (19), and WlbG and WlbL lack all three sugars (17,18). Homology studies have suggested that WlbL fails to produce the first sugar in the trisaccharide, while WlbG retains the ability to produce this sugar, but fails to transfer it to the surface of the bacterial cell (18).…”

Multiple Roles forBordetellaLipopolysaccharide Molecules during Respiratory Tract Infection

“…Examples include the genes and operons that encode a motility apparatus (2, 3), the pertussis toxin (7), and possibly a type III secretion system (28, 29). These differentially expressed factors are likely to contribute to subspeciesspecific characteristics such as host specificity and the ability to cause pathology and to persist.The lipopolysaccharide (LPS) molecules expressed on the surface of B. pertussis, B. parapertussis, and B. bronchiseptica also differ substantially (4,5,17,23). The observation that LPS structures are regulated by the BvgAS virulence control system suggests that these molecules play a role in respiratory tract infection (16,17).…”

“…The lipopolysaccharide (LPS) molecules expressed on the surface of B. pertussis, B. parapertussis, and B. bronchiseptica also differ substantially (4,5,17,23). The observation that LPS structures are regulated by the BvgAS virulence control system suggests that these molecules play a role in respiratory tract infection (16,17).…”

“…The locus is flanked on one side by Bvg accessory factor (baf) and waaA and waaC, which encode the LPS biosynthesis functions 2-keto-3-deoxyoctulosonic acid transferase and heptosyltransferase, respectively. In B. bronchiseptica and B. parapertussis, the other side is flanked by the LPS O-antigen biosynthetic locus (23). In B. pertussis, this locus has been replaced by an insertion sequence.…”

Epitope of the Vaccine-TypeBordetella pertussisStrain 186 Lipooligosaccharide and Antiendotoxin Activity of Antibodies Directed against the Terminal Pentasaccharide-Tetanus Toxoid Conjugate

“…This molecule plays a major role in the host-pathogen interactions (46) and is responsible for endotoxic activities similar to those of enteric bacteria (1,50). (4), which consist of a lipid A moiety linked to a core nonasaccharide or a dodecasaccharide.…”