Neutralization of the Biological Activity of Erythropoietin by Immune Sera*

Abstract
Erythropoietin has been thought to possess only slight antigenicity (Jacobson, Goldwasser and Gurney, 1959; Lowy, Keighley, Borsook and Graybiel, 1959). Schooley and Garcia (1962a), however, recently reported the production of neutralizing antibodies to human urinary erythropoietin. The present report describes the production of antibodies against sheep plasma erythropoietin and confirms and extends the observations of Schooley and Garcia.