Evidence for a Primary Association between Immunoblasts and Small Gut

Abstract

SINCE the observations of Gowans and Knight¹ it has been shown that many of the lymphoid blast cells (immunoblasts) that appear in the thoracic duct lymph of rats after immunization of the caudal lymph nodes with a variety of antigens “home” to the lamina propria of the small gut², where they differentiate into plasma cells³. The immunological specificity of the immunoblasts, however, does not seem to affect their affinity for the small gut^2,3. Recent work⁴ has shown that immunoblasts home just as readily to the small gut of unsuckled, neonatal rats obtained by Caesarian section, in which the gut is sterile and presumably antigen-free, and where there is no influence of endogenous or maternal colostral immunoglobulins. The entry of immunoblasts into the lamina propria must involve the transmigration of these cells across the vascular endothelium. The first event in such a process may be the engagement of a receptor on the surface of the immunoblast with a complementary group on its endothelial surface. We have studied the entry of immunoblasts into “free” grafts of syngeneic foetal gut, implanted subcutaneously, and the entry of xenogeneic immunoblasts into normally situated gut.