Biological activity of bacterial surface components: bacterial extracts and defined bacterial cell wall components as immunomodulators.

Bacterial extracts obtained from pathogenic strains occurring in lung infections (Broncho Vaxom) or urogenital infections (Urovaxom) as well as defined surface components of Gram-negative bacteria purified from bacteria or obtained by chemical synthesis were tested for their immunomodulatory properties in a murine system. The bacterial extracts were able to act as immunogens inducing an antigen-specific response. Both the bacterial extracts and the purified bacterial cell wall components constituted polyclonal activators of murine splenic B cells, as demonstrated by proliferation assays measuring the incorporation of [3H]thymidine into DNA. They were also able to act as immunoadjuvants increasing the SRBC and the BSA-TNP specific immune response, and could induce tumor cytotoxicity in bone marrow-derived macrophages. The results show that bacterial extracts and defined bacterial surface components constitute immunogens as well as immunomodulators in vitro and in vivo.