Abstract
Purpose: :
We wanted to investigate antigen specific in vitro responses of intraocular T cells from patients with various uveitis entities.
Methods: :
Lymphocytes from anterior chamber taps from patients with endogenous and infectious uveitides were collected with patient’s informed consent and aspecifically expanded to T cell lines (TCL) by cultivation with PHA, IL–2 and autologous PBMC and allogeneic B–LCL as feeders for about 2 weeks. Proliferation assays were performed by cultivating these TCL with irradiated autologous PBMC and 22 different antigens (various peptides from IRBP, retinal S–Antigen, mimotopes, recall and control antigens and mitogen) for 5 days, then pulsed with [3H]–thymidine. Supernatants were collected daily and pooled for multiplex cytokine/chemokine analysis.
Results: :
Proliferation to retinal antigen/peptides and mimotopes (stimulation index > 2) was only observed in 8 of 25 TCL from endogenous, and in 3 of 8 infectious (herpetic) uveitis samples, but in none of the 8 controls or in PBMC cultures. Cytokine and chemokine secretion levels did not correlate with the T cell proliferation data. The majority of the supernatants of antigen–stimulated TCL cultures contained increased levels of IL–8, MCP–1, MIP–1alpha and IL–6. Secretion of both Th1 and Th2 cytokines was detected in the PHA–stimulated TCL cultures. No distinct Th1 cytokine pattern was found.
Conclusions: :
There was no correlation of preferential antigen recognition with certain types of uveitis, nor of antigen–specific T cell proliferation with cytokine or chemokine secretion. These data raise two questions: 1 – Are T cell proliferation or cytokine secretion the optimal methods to detect antigen–specific immune responses. 2 – Are T cells reactive to known retinal autoantigens or their mimotopes involved in maintaining intraocular inflammation in both endogenous and exogenous uveitis.
Keywords: autoimmune disease • cytokines/chemokines • uveitis-clinical/animal model