Lymphocyte recognition of lymph node high endothelium. II. Characterization of an in vitro inhibitory factor isolated...

Thoracic duct lymph contains a factor that inhibits in vitro adhesion between lymphocytes and high endothelial cells. Crude inhibitory factor was isolated from lymph by (NH4)2SO4 precipitation and partially purified by using an immunoabsorbant column of rabbit anti peak I Ig coupled to Sepharose 4B. Antibody affinity chromatography separated the HEV binding inhibitory factor from the bulk of protein in the crude preparation; activity was enriched 50-fold. The results show that the effect of the factor was exerted on high endothelial cells; both glutaraldehyde-fixed HEV and unfixed mouse HEV were susceptible to the action of this material. In contrast, the HEV binding properties of lymphocytes were unaffected by the factor. Inhibitory activity was destroyed by treatment with trypsin or exposure to 100 degrees C but was unaffected by incubation at 56 or 70 degrees C for 30 min. In addition, the factor bound to lentil lectin and was eluted with alpha-methyl-D-mannoside. Together these findings indicate that the HEV binding inhibitory factor is a glycoprotein.