Biological Properties of Cell Fragments of 'Neisseria meningitidis'.
Abstract:
Several fractions have been extracted from the cell envelope of Neisseria meningitidis group B and characterized with regard to their morphology, antigenicity, protein composition, and toxicity. Cell membrane-enriched and cell wall- entriched fractions were obtained by the distruption with the French pressure cell of whole bacterial cells in a medium of low ionic strength and the subsequent separation of fragments of similar density on sucrose gradients. In addition, fractions have been extracted from the cell envelope based on the differential solubility of envelope proteins in the nonionic detergent, Trition X-100. The trition soluble fraction contains predominantly cytoplasmic membrane proteins and the Triton insoluble fraction contains cell wall proteins. The Triton insoluble fraction was further treated with Triton and EDTA to yield a fraction TritionTriton-EDTA insoluble which still contains cell wall protein but which apparently has reduced lipopolysaccharide content. Sera from rabbits immunized with the various fractions formed precipitin lines in immunodiffusion studies. Preliminary toxicity data indicate that all fractions are contaminated with LPS, the TritonTriton-EDTA insoluble fraction showing the lowest level of toxicity and consequently holding the most promise as an immunizing agent. Modified author abstract