Related Experiment Video
Updated: Jul 13, 2026

Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction
Published on: May 28, 2012
The lipooligosaccharide immunotype as a virulence determinant in Neisseria meningitidis
Abstract:
We have studied the antigenic (immunotype) and physical characteristics of the lipooligosaccharide (LOS) of epidemiologically related Neisseria meningitidis case (36) and carrier (76) isolates associated with a virulent clone of meningococci (ET-5 complex). LOS immunotypes were determined by dot blotting using immunotype specific monoclonal antibodies and physical characteristics were determined from silver stained SDS-PAGE following proteinase K digestion. The genetic similarity of the different isolates was confirmed by analysis of the restriction fragment length polymorphisms. An association between LOS immunotype expression and invasive disease was found; 97% of case isolates expressed the L3,7,9 immunotype, of which 13% additionally expressed the L1,8,10 determinant. The LOS immunotypes of carrier strains were much more heterogeneous. The predominant immunotype was L1,8,10 (70%) and only 24% expressed L3,7,9 alone. Genotypically related case isolates from Norway (6) and Austria (18) expressed the L3,7,9 immunotype with similar frequency to the U.K. isolates. The combination of LOS immunotype and capsule expression appears to be related to the virulence of these meningococcal strains.
Related Concept Videos
Formation of Lipopolysaccharides
Determinants of Bacterial Pathogenicity and Virulence
Regulation of Bacterial Virulence
Bacterial Meningitis
Bacterial Meningitis II: Pathophysiology

