Evidence for multiple CD95-CD95 ligand interactions in anteriorchamber-associated immune deviation induced by soluble protein antigen

We have investigated whether CD95-CD95 ligand interactions are important in anterior chamber-associated immune deviation (ACAID) induced by soluble protein antigen, and if so, to identify the participating cells on which these molecules are expressed. Peritoneal exudate cells as antigen-presenting cells (APC) obtained from B6.lpr/lpr, B6.gld/gld and C57BL/6 mice were cultured with ovalbumin (OVA) and transforming growth factor-beta 2 (TGF-beta 2) overnight, then injected intravenously into C57BL/6 or B6.lpr/lpr recipients. Some B6.lpr/lpr mice were reconstituted with naive T cells from wild-type C57BL/6 donors. In other experiments, B6.lpr/lpr and B6.gld/gld mice received an anterior chamber injection of OVA followed 7 days later by subcutaneous immunization with OVA plus adjuvant. Delayed hypersensitivity (DH) was assessed with an ear swelling assay. T cells activated in vitro with OVA-pulsed, TGF-beta-treated APC were tested in vivo for their capacity to suppress DH expression in a local adoptive transfer assay. The results indicate that when ACAID was induced by in-vitro generated ACAID-inducing cells, the APC expressed CD95L, and recipient T cells expressed CD95. The capacity of in vitro generated regulatory T cells to suppress DH expression to OVA in vivo was not governed by CD95-CD95L interactions. When OVA was injected into the anterior chamber of naive mice, CD95 expression was required for ACAID induction, although ACAID was readily induced in CD95L-deficient mice. We conclude that CD95-CD95L interactions are required in ACAID for the initial stage of APC presentation of eye-derived antigens to T cells, and that CD95-CD95L interactions participate at one or more additional step in the process by which ACAID is induced by soluble protein antigens.