The endotoxin which leads to endotoxic shock is actually -

Endotoxin s heat stable lipopolysaccharides which form an integral pa of the cell wall of gram negative bacteria . their toxicity depends on lipid component . they are released only by the disintegration of the cell wall . they cannot be toxoided. they are poor antigens and their toxicity is not completely neutralised by the homologous antibodies . they are active only in relativly large doses Ref: Ananthanarayan & paniker's Textbook of microbiology 9th edition pg no 74