The response of cultured human kidney capillary endothelium to immunologic stimuli

We have developed in culture for the first time one of the actual target cells in kidney rejection by establishing long-term cultures of human kidney capillary endothelium and have begun to explore their response to immunologic stimuli. Microvascular endothelial cells were obtained from the human kidney cortex by mechanical separation, enzyme digestion, and density gradient centrifugation. The cells were exposed to 1% PHA, a PHA-stimulated PBL supernatant, human and mouse IL-1 and human gamma-interferon. They were stained with FITC-conjugated monoclonal antibodies specific for beta 2-microglobulin, HLA-DR, and DQ and analyzed by flow cytometry (FACS-II). HKCE cells express HLA-ABC antigens during growth and confluent phases but do not express DR or DQ antigens. Only the PHA-stimulated PBL supernatant and gamma-interferon induced class II antigen expression. A change in cellular morphology was noted after 72 hr of incubation in the presence of the lectin-stimulated PBL supernatant. Our findings show that microvascular endothelial cells express selected Ia antigens only after immunologic induction. This is in agreement with studies using umbilical and aortic endothelial cells. These data suggest that a dynamic interaction takes place between activated lymphocytes whose products induce expression of class II antigens and human kidney endothelial cells.