“…Introduction j^^^.^^ nttmber of toxic and other host reac-Lipopolysaccharides (LPS) of the cell wall tive properties, collectively described as enof Gratn-negative bacteria are macromole-dotoxjc. ctilar strtictures contaitiing polysaccbaride, LPS are released both from autolyzing phospholipid and stnall quanitittes of protein, bacterial cells antl from live orgatiisms as These tnacromolectilar cotnplexes incorpo-well (Cmtchley et al 1967, Fraok & Houver 1969, Most likely, such release takes place into the plaque matrix (Mergenhagen et al, 1961, Berglund et al 1969, Selvig et al, 1971, Endotoxic activity of human gingival exudate has also been demonstrated (Simon et al, 1969), Gingival tissue is highly susceptible to endotoxin derived from plaque bacteria (Rizzo & Mergenhagen 1964, Taichman & Courant 1965, and endotoxic LPS has, therefore, been discussed as a possible pathogenetic factor in periodontal disease (Mergenhagen et al 1961, Scherp 1962, Rizzo & Mergenhagen 1964, Gustafson et al, 1966, Rizzo 1968, Selvig et al, 1971, Schwartz et al, 1972, Simon et al, 1972. In addition, endotoxin may have etiological significance in the resorption of bone (Rizzo & Mergenhagen 1964, Hausmann et al, 1972,…”