Lipopolysaccharide acts directly on B lymphocytes to increase DNA synthesis, thus promoting B lymphocyte division, so lipopolysaccharide is a non-specific mitogen of B lymphocytes.

Lipopolysaccharide has immunogenicity, that is, they can stimulate B lymphocytes to produce specific antibodies. Immunization with lipopolysaccharide produces polyclonal antibody reactions, mainly synthesizing IgM, occasionally IgG, and IgA.

B cells are divided into two subtypes: B1 and B2. B1 is mainly distributed in the abdominal cavity of mature mice and can express CD14, CD5, CD44, and CD116; However, B2, the normal B cell, has no expression of CD14 and CD44 molecules. CD14mRNA A can be detected in mouse abdominal cavity B1 cells, but there is no CD14mRNA in spleen B2 cells. B1 can activate at low endotoxin levels and can inhibit NF when an anti-CD14 antibody is added- κ B. Protein synthesis. B2 cells have no activation effect at low endotoxin concentrations and only activate at high endotoxin concentrations. It can be seen that CD14 of B1 can accelerate LPS-induced activation.

The mitogenic activity and immunogenicity of lipopolysaccharide are one of the mechanisms of anti-infection, and it also participates in the occurrence and development of some pathological processes. For example, when pestis is infected, the bacteria multiply in the phagocytes in the lymph nodes, and lipopolysaccharide stimulates B lymphocytes, which proliferates around the germinal center of the lymph nodes, leading to lymph node enlargement.

Wahl et al. reported that lipopolysaccharide can activate B and T cells to produce lymphatic factors, such as monocyte chemokine and macrophage activating factors. It has been confirmed that lipopolysaccharide can directly activate B lymphocytes to produce lymphokines while activating T lymphocytes requires the involvement of macrophages.