Described herein is a method for removing toxic lipooligosaccharide (LOS)
from outer membranes of Gram-negative cocci, such as Neisseria meningitidis.
LOS-depleted outer membranes and LOS-depleted soluble outer membrane proteins can
be prepared, which are able to elicit bactericidal antibodies against homologous
strains of bacteria. Vaccines and other uses of the preparations are further described.
