Kinetics of cytokine production in experimental autoimmune anterior uveitis (EAAU).

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.