Activation of mononuclear immune cells in response to staphylococcal lipoteichoic acid

The goal of the present study was to evaluate the influence of staphylococcal lipoteichoic acid (LTA) on the activation of mononuclear immune cells. A murine tumor necrosis-like factor (TNF-like) was induced in the sera of CD-1 mice which had been primed with heat/formalin-inactivated Propionibacterium avidum KP-40 and subsequently exposed to LTA extracted from Staphylococcus saprophyticus strain S 1. Monoclonal antibody against murine TNF (anti-TNF) significantly inhibited the cytostatic activity of mice sera against transformed L-929 cells. Freshly isolated lymphocytes did not display interleukin 2 (Il-2) receptors, but receptors were expressed on Con A incubated cells and in significantly higher numbers after coexposure to staphylococcal LTA in vitro. Since the induction of TNF (macrophages) and Il-2 receptors (lymphocytes) represent stimulation of the mononuclear immune system, staphylococcal LTA may be considered to be an immunomodifier.