lipooligosaccharide

lipo·ol·i·go·sac·cha·ride (LOS) (lip″o-ol″ĭ-go-sakґə-rīd) any of a group of substances consisting of a lipid A component linked to an oligosaccharide; they resemble lipopolysaccharides but do not have long polysaccharide side chains. They are found associated with porin on the outer membrane of certain gram-negative bacteria. In some strains of pathogenic bacteria such as Neisseria gonorrhoeae, Neisseria meningitidis, and Moraxella catarrhalis, they may be biologically active, producing endotoxins or contributing to the cell's resistance to antibiotics.