Tubular epithelial cells as accessory cells for superantigen-induced T cell activation

In various inflammatory kidney diseases, tubular epithelial cells (TEC) express major histocompatibility complex class II antigens. To assess whether they might have the capacity to directly activate T cells, human TEC in culture were treated with gamma interferon to induce class II expression. TEC were then cocultivated with staphylococcus enterotoxin and cloned T cells or highly purified peripheral T cells. After 1-2 days, release of interleukin 2 and of gamma interferon was seen; after 3-5 days T cell proliferation occurred. The proliferation could be inhibited by antibodies to class II antigens or by antibodies to ICAM-1; the latter is also expressed on TEC in inflammatory processes and on TEC in culture as well. In conclusion, human TEC might function as accessory cells for T cell activation and might support T cell dependent immune response.