Expression of cytokine mRNAS in the draining lymph nodes following contact sensitivity in mice

To clarify in vivo cytokine profiles during the afferent phase of contact sensitivity, balb/C mice were sensitized by topical applications of 2.5% 1-chloro-2,4-dinitrobenzene (DNCB) and 3% 4-ethyoxymethylene-2-phenyloxazol-5-one (OXAZ), respectively. On day 6 of contact sensitization, total RNA was extracted from the draining lymph nodes. Expressions of Th1 and Th2 cell-related cytokine mRNAs were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Among the 8 cytokine mRNAs observed in naive nice, the mRNAs for IL-2, IL-4, IL-10, IL-12p35, IL-12p40, and IFN-gamma were constitutively expressed weakly, whereas IL-5 and IL-13 mRNAs were undetectable. Contact sensitization with DNCB or OXAZ significantly up-regulated the expressions for Th1 cell-related cytokine mRNAs such as IL-2, IL-12p35, IL-12p40, and IFN-gamma, in particular IL-2 and IFN-gamma genes. Moreover, in Th1 cytokine cases, the Th2 cytokines including IL-4, IL-5, IL-10, and IL-13 mRNAs were significantly induced or augmented in the draining lymph nodes. Among the 4 Th2 cytokine mRNAs, both contact allergens showed a much greater inducing effect on IL-4 mRNA than the other cytokines. Furthermore, OXAZ, a stronger sensitizer than DNCB, was confirmed to be much stronger than DNCB in inducing expressions of cytokine mRNAs. The study indicates that contact allergens may induce mixed expressions of both Th1 and Th2 cytokine mRNAs, not just Th1 cytokine mRNAs, in the draining lymph nodes at least at 6 days following contact sensitivity.