A primary immune response of Bufo marinus spleen cells in vitro

Single-cell suspensions of Bufo marinus spleen have been induced to produce a primary immune response to a soluble purified protein. Using polymerized flagellin from Salmonella adelaide as antigen and culture conditions commonly available in most laboratories but new for amphibian cells, it has been found that in vitro at 37 degree C, toad spleen cells produce an antibody-forming cell response optimal at day 6. The response depends on the number of cultured cells and dose of antigen, and parallels that obtained in vivo. The optimal immune response is preceded at day 4 by the peak uptake of tritiated thymidine. The antibody-forming cell response is suppressed in the presence of allogeneic serum.