Hepatic and Splenic Phagocytosis of Isophilic and Heterophilic Antigens in Immunized Rats 1

Abstract

Summary

Hepatic and splenic uptakes of ⁵¹Cr-labeled sheep red cells (SRC) were significantly depressed in adult rats which had previously been immunized with heterophilic antigen (HA, boiled homogenate of guinea pig kidney). Uptake of ⁵¹Cr-labeled HA was not affected by preimmunization. Administration of HA to newborn rats significantly depressed uptake of ⁵¹Cr-SRC, but not of ⁵¹Cr-HA, given 10–13 weeks later. Administration of SRC to newborn rats failed to interfere with uptake of ⁵¹Cr-SRC or ⁵¹Cr-HA later in life. Since these observations parallel the reduced formation of antibodies for SRC in rats preimmunized with HA, the changes in phagocytosis and immune responses may be attributable to imprinting of numerous macrophages with receptors specific for HA. Subsequently introduced SRC may thus be diverted to HA-specific macrophages and be prevented from contact with macrophages better equipped to phagocytose and process this substrate containing both heterophilic and isophilic antigens.