Modulation of concanavalin A stimulation of hamster lymphoid cells by lithium chloride.

Addition of LiCl (1–25 mM) to serum-free cultures of MHA hamster thymocytes, lymph node cells, or splenocytes stimulated with concanavalin A had a biphasic effect on ³H]thymidine incorporation. These concentrations of LiCl enhanced stimulation of ³H]thymidine incorporation by suboptimal levels of concanavalin A but inhibited stimulation of optimal and supraoptimal concentrations of concanavalin A. This effect was specific for Li⁺ since it was not observed when similar concentrations of Na⁺, K⁺, or Mg²⁺ were added to cultures stimulated by concanavalin A. The inhibitory effect of LiCl on concanavalin A stimulation was not reversed by addition of Na⁺, Ca²⁺, Mg²⁺, or Ca²⁺ + Mg²⁺ to the cultures. Significant reversal of LiCl inhibition of stimulation was observed when KCl was added to the cultures. However none of the ions tested blocked the Li-induced enhancement of ³H]thymidine incorporation in the presence of suboptimal concentrations of concanavalin A.