Cell walls, peptidoglycans, and teichoic acids of Gram-positive bacteria as polyclonal inducers and immunomodulators of proliferative and lymphokine responses of human B and T lymphocytes.

In this study the mitogenic and immunomodulating effects of bacterial cell wall preparations were investigated. Cell walls, peptidoglycans, and teichoic acids from Bacillus subtilis and Staphylococcus aureus Wood 45 activated both human T cells (supplemented with 10% monocytes) and B cells to proliferate and to produce leukocyte-inhibitory factor. Similar results were obtained with adult and umbilical cord blood cells, suggesting that these bacterial preparations were acting as mitogens. Cell walls and peptidoglycans had a modulating effect on purified protein derivative- or protein A-induced proliferation. In the presence of suboptimal concentrations of these stimulants, bacterial components enhanced the proliferative response. However, at optimal concentrations of purified protein derivative or protein A, bacterial components suppressed lymphocyte proliferation. Peptidoglycans solubilized by lysozyme activated B lymphocytes but not T cells. Solubilization had no effect on the immunomodulating capacity.