The host-mediated systems can be divided into the cell and humoral-mediated systems. The former refers to neutrophils, platelets, monocytes, macrophages, lymphocytes, basophils, mast cells, dendritic cells, and endothelial cells; The body fluid system is a complement and coagulation system. Endotoxin acts on the stem-mediated system. On the one hand, it plays its defense function, on the other hand, it also causes some pathological processes.

1. Effect on the complement system

Endotoxin molecules on bacteria, free endotoxin molecules, and analogs of lipid A can activate complement, activate complement through classical and alternative ways, play a natural immune response effect, and swallow pathogens and their products; In the process of the immune response, it can activate the acquired immune response, make a variety of cytokines express, and bring beneficial and adverse effects to the host.

2. Effect on the blood coagulation system

Endotoxin can affect the blood coagulation system of the body, leading to the occurrence of disseminated intravascular coagulation. It has been proved by animal models, the human body, and in vitro experiments that endotoxin can activate Hageman factor (coagulation factor III, contact factor) and activate endogenous coagulation pathway. On the other hand, endotoxin can also activate the exogenous coagulation pathway. The procoagulant activity of endotoxin is mainly manifested in lipid A. After the activity of endotoxin is inactivated by polymyxin B, its procoagulant effect also disappears.