Immunological Restoration of the Locally Irradiated Spleen with Circulating Lymphocytes

Abstract

ALTHOUGH the production of haemolysins by normal rats after a single intravenous injection of sheep red blood cells (SRBC) occurs almost entirely in the spleen, heavy local irradiation of this organ can drastically reduce the capacity of the animal to form haemolysin only if combined with sublethal total body irradiation. Irradiation of the spleen alone, when performed shortly after administration of SRBC, results in an apparently normal haemolysin response which derives almost completely from the activity of the irradiated spleen¹. There is little doubt that the doses of radiation used (about 10,000 r.) kill all lymphoid cells in the spleen at the time of irradiation², so it is clear that the restoration of the response to an antigenic stimulus must derive, in these circumstances, from a circulating cell population³. This cell population has been investigated in two ways: first, by limiting the time available for the appropriate cells to migrate into the spleen, and second, by supplementing the radiation depleted circulating pool with suitable cells.