Nature of the Antigens responsible for the Acquired Tolerance of Turkeys to Rous Sarcoma Agent

Abstract

THE original observations of Simonsen and Harris^1,2 that tolerance in turkeys to Rous sarcoma agent could be produced by inoculating turkey embryos or one-day-old poults intravenously with normal whole blood from the strain of fowls in which the tumour was propagated, has been confirmed by Svoboda and Hasek³. It soon became apparent⁴ that living cells were not required for the transmission of this tolerance. This was of great interest, because Billingham, Brent and Medawar⁵ found that the capacity of whole blood to confer tolerance to tissue transplantation resides entirely in the leucocyte fraction, the antigens responsible apparently being those of the cell nucleus. Antigens of spleen cell nuclei have been shown to confer transplantation immunity when injected into immunologically mature animals⁶, but transplantation tolerance has, as yet, only been conferred upon embryos and immunologically immature animals in the presence of intact donor cells. The two questions to which we addressed ourselves were, therefore: (1) Was this tolerance of the tissue transplantation or of the serum antibody type? (2) Was a single antigen involved and, if so, what was it and what was its relationship to the antigens of the Rous agent?