Bacterial‐Endosymbiote‐Derived Lipopolysaccharides on Amoeba Symbiosome Membranes

Abstract

ABSTRACT. Monoclonal antibodies were obtained against lipopolysaccharides of Gram‐negative bacterial endosymbiotes in amoebae and were used to determine the origin and distribution of the antigens. The lipopolysaccharides were located on endosymbiote's surfaces as determined by indirect immunofluorescence staining under both light and electron microscopes. In addition, host symbiosome membranes enclosing the endosymbiotes also contained the same lipopolysaccharides on the cytoplasmic side as shown by indirect immunofluorescence staining after intracellular injection of anti‐lipopolysaccharide antibodies. This is the first report for the presence of symbiote‐derived lipopolysaccharides on the host symbiosome membranes, and their possible roles are discussed in relation to the prevention of lysosomal fusion with symbiosomes.