THY-1 ANTIGEN - SELECTIVE ASSOCIATION IN LYMPHOID ORGANS WITH THE VASCULAR BASEMENT-MEMBRANE INVOLVED IN LYMPHOCYTE RECIRCULATION

Abstract

The cell surface differentiation antigen, Thy-1, was demonstrated by immunofluorescence to be associated with collagen-based connective tissue (mainly basement membrane) around some blood vessels in rat lymphoid organs. This association is highly selective. Only certain types of blood vessel within a given lymphoid organ were Thy-1+. Different lymphoid organs (thymus, bone marrow, lymph node and spleen) had characteristic differences in types of blood vessel that bear Thy-1. In lymph node and spleen the vessels that were Thy-1+ were involved in lymphocyte recirculation and homing (post-capillary venules and arterioles of white pulp). The possibility that Thy-1 may function in mediating selective adhesion of small lymphocytes to extracellular substrates during recirculation was discussed.