Production of an antibody-like factor in the sea star Asterias rubens: involvement of at least three cellular populations.

Cells from the axial organ of sea stars stimulated in vivo with TNP coupled to polyacrylamide beads and subsequently cultured in vitro were able to produce an antibody-like factor which induced the lysis of mammalian red cells sensitized with TNP. The axial organ cells were fractionated in two populations, adherent and non-adherent to nylon wool. The release of the antibody-like factor required the contact of both populations. When the adherent cells were disrupted by sonication the factor was not produced, but the non-adherent cells could be substituted by their membranes. Destruction by silica of the phagocytic cells present in the adherent population inhibited the production of the factor. The addition of mercaptoethanol to the cultures was essential and did not neutralize the effect of silica. It is concluded that at least three types of cells are involved in the production of the antibody-like factor adherent and non-adherent cells, and phagocytes.