Immunomodulatory Effects of Bacterial Lipopolysaccharide

Abstract

The most easily discernible and characteristic result of interaction of LPS with the immune system are the activation of B cells to divide and/or synthesize and secrete immunoglobulin. LPS as an antigen or carrier for chemically defined haptens induces a T independent antibody response, while antibody responses to unrelated T dependent antigens are modulated by LPS. Such regulation can be explained both by increased susceptibility of B cells to regulation after interaction with LPS, and increased activity of regulatory cells after their interaction with LPS. Studies of these mechanisms have exploited the availability of several strains of mice which are genetically poorly responsive to LPS and thus have helped to define the genetic basis of LPS responses. In addition, these studies have demonstrated the existence of other bacterial cell wall components which have some of the immunological properties of LPS but are not susceptible to the same genetic control. Future studies on the molecular nature of the interaction of LPS with target cells and the biochemical basis of cell triggering should yield interesting information on the cell biology of cell activation.