Mice immunization with gel electrophoresis micropurified bacterial lipopolysaccharides

Some evidence on the possible use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to elicit antibodies against smooth- or roug h-type bacterial lipopolysaccharides (LPS) is shown. Gel-separated LPS were negatively stained with zinc-imidazole to precisely localize the bands of interest under fully reversible conditions. Then the bands of interest were excised and the resulting gel slices washed in a solution of a zinc-comple xing agent (e.g., 100 mM EDTA), after which they were extruded through a me tal sieve of 32 mu m average size contained in a 1 mt syringe, to generate homogeneous gel microparticles. The LPS-containing gel slurries were used d irectly to immunize female BALB/c mice. Using this procedure, positive mous e polyclonal antibody responses against gel-purified smooth- or rough-LPS f orms from Escherichia coli K-235 or Bordetella pertussis were elicited, as tested by a dot-immunoblotting assay. Our results may encourage the use of SDS-PAGE-micropurified LPS to develop optimized immunization procedures for the generation of specific antibodies against LPS bands of defined sizes, and therefore they constitute an intermediate step toward that aim.