Purpose: Experimental autoimmune anterior uveitis (EAAU) can be induced in Lewis rats with bovine melanin associated antigen (MAA) extracted from the iris/ciliary body (CB) and does not require adjuvant. The present investigation was undertaken to study the expression of various cytokines in EAAU.
Methods: Lewis rats were immunized with bovine MAA and sacrificed at various time points. The iris/CB and popliteal lymph nodes were harvested, and total RNA isolated. The reverse transcription polymerase chain reaction (RT-PCR) was utilized to determine the mRNA expression of IFN-gamma, TNF-alpha, IL-2, IL-4, IL-6 and IL-10.
Results: TNF-alpha mRNA levels in iris/CB paralleled the course of EAAU and increased dramatically at the peak of disease. However, mRNA levels of TNF-alpha demonstrated little change in the popliteal lymph node. IFN-gamma mRNA was barely detectable in the iris/CB and increased only slightly at the peak of disease. In contrast, IFN-gamma mRNA levels in the popliteal lymph node paralleled the course of disease and increased during the peak of disease. IL-10 mRNA did not change in the iris/CB but increased modestly in the popliteal lymph node. IL-2, IL-4, and IL-6 mRNA levels did not change during the course of EAAU in either tissue.
Conclusions: Our study reveals an interesting correlation between the expression of TNF-alpha, IFN-gamma and disease progression in EAAU. Furthermore, they suggest that TNF-alpha is an important cytokine in the target tissue, while IFN-gamma is in the draining lymph node.