Stimulation of sea star Asterias rubens axial organ B-like cells by Nocardia-delipidated cell mitogen and derived fractions.

The axial organ (AO-cells) of the starfish Asterias rubens is a primitive immune organ. The total population was fractionated into two populations: adherent (B-like) and non-adherent (T-like) to nylon wool. Nocardia-delipidated cell mitogen (NDCM), Nocardia water soluble mitogen (NWSM), NWSM-pellet (NWSMP) and purified cell walls (CW) from Nocardia opaca induce the proliferation of B-like cells from the axial organ. The Nocardia immunomodulators studied are inactive on the total and T-like population. The mitogenic activity of B-like cells requires the presence of phagocytic cells.