Effect of polyclonal B-cell activators on DNA synthesis in fibroblasts

The polyclonal B-cell activators (PBA) lipopolysaccharide (LPS), type III pneumococcal polysaccharide (SIII), dextran, dextran sulphate, pentosan sulphate, and polyvinylpyrrolidone (PVP) were found to cause an increased DNA synthesis in mouse fibroblast monolayer cultures in the presence of calf serum, provided the background cpm were within certain values. The same PBA suppressed DNA synthesis when the cultures showed high background [corrected] cpm. Since the PBA did not activate DNA synthesis in serum-free cultures, it was concluded that PBA could be directly activate fibroblasts but rather influenced factors responsible for regulation of DNA synthesis in fibroblasts. In contrast PBA directly trigger lymphocytes.