, Volume 40, Issue 4, pp 393–394

Simplification of the ecdysteroid radioimmunoassay by the use of protein A fromStaphylococcus aureus


  • J. T. Warren
    • Department of BiologyUniversity of North Carolina
  • W. Smith
    • Department of BiologyUniversity of North Carolina
  • L. I. Gilbert
    • Department of BiologyUniversity of North Carolina
Short Communications

DOI: 10.1007/BF01952570

Cite this article as:
Warren, J.T., Smith, W. & Gilbert, L.I. Experientia (1984) 40: 393. doi:10.1007/BF01952570


Three methods of separating antibody-bound ligand from free ligand were compared for an ecdysteroid radioimmunoassay. Ecdysteroid antibody concentration and ligand specific radioactivity were adjusted to measure 2 ranges of ecdysone concentrations (0.01–2.0 ng and 0.25–32.0 ng). In comparison with the tradiotional separating agent, ammonium sulfate, neither protein A nor polyethylene glycol altered sensitivity or specificity of the radioimmunoassays. The protein A immunoglobulin precipitation method is quick and simple, making it a preferred alternative protocol for terminating ecdysteroid radioimmunoassays.

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© Birkhäuser Verlag 1984