Antigen Capture in Chicken Spleen during the Primary Immune Response and Relationship to Phagocytic Activity

Abstract

THE localization of antigen in the lymph nodes and spleens of mammals has been extensively studied¹. Little information is available, however, on the distribution of antigen in the fowl. The chicken has no lymph nodes, and so the spleen is its main peripheral lymphoid organ. The principal role in antibody production is therefore attributed to the spleen^2–4, although the immune responsiveness of diffuse organ-associated lymphoid tissue⁵ cannot be neglected. The immunofluorescence and autoradiographic studies of White et al.^6,7 focused on the antigen trapping capacity of secondary splenic follicles and periarteriolar reticular cells. Present experiments in this laboratory, using ¹³¹I-labelled or ¹²⁵I-labelled bovine serum albumin (BSA), have shown a marked retention of antigen in the chicken spleen, chiefly by red pulp macrophages and reticulum cells forming the Schweigger-Seidel capillary sheaths. The capacity of macrophages for antigen uptake stems from their phagocytic activity, whereas antigen capture by Schweigger-Seidel sheaths is probably unrelated to phagocytosis.