Muramyl dipeptide-induced changes in murine splenocyte responses to concanavalin A

The effect of muramyl dipeptide (MDP) on Con A-stimulated activation of murine spleen cells was studied. MDP was found to enhance or suppress the proliferative response of splenocytes when different concentrations of Con A were used. MDP was shown to change the IL-2 content in culture supernatants of stimulated cells and to influence IL-2-dependent proliferation of Con A-blasts. A high degree of correlation was found between the proliferation of Con A-blasts and the expression of IL-2 receptors on Con A-blasts. This correlation, however, disappeared in the presence of MDP. The effects of MDP were shown to depend on the level of initial cell activity or rather on conditions leading to a given initial activity of cells.