L-rhamnose inhibits proliferation of murine splenocytes by the lipopolysaccharide and polysaccharide moiety of Shigella dysenteriae type 1 lipopolysaccharide.

The induction of proliferation of murine splenocytes by lipopolysaccharide (LPS) of Shigella dysenteriae type 1 and its polysaccharide (PS) and lipid A fractions was investigated. The LPS-induced proliferation reached a maximum at a concentration of 30 ng/ml. The PS and lipid A induced proliferation of murine splenocytes at similar concentrations. Preincubation of murine splenocytes with varying concentrations of L-rhamnose blocked LPS- and PS-induced proliferation in a dose-dependent manner. The lipid A-induced stimulation, on the contrary, was not affected by preincubation of the cells with L-rhamnose. These data suggest that activation of splenocytes by LPS and PS is mechanistically different from that induced by lipid A and is presumably involved in the specific recognition of carbohydrate structures on LPS and PS.