Immunomodulatory roles of topical dinitrochlorobenzene treatment in Herpes simplex virus infection

Epicutaneous application of a contact sensitizer 2, 4-dinitro-1-chlorobenzene (DNCB) is known to cause an inflammatory response and a hapten-specific T cell activation. We developed a highly stable gel formulation for DNCB which is easy to apply to the skin. The present study focused on whether topical application of DNCB gel produced immunomodulation with prophylactic effects against lethal herpes simplex virus infection (HSV) type 1. Our results indicated that topical treatment with DNCB gel induced proliferation of lymph node cells, T cells as well as antigen presenting cells, the production of cytokines, especially IFN-γ, and cutaneous inflammatory response comparable to that from freshly prepared DNCB in olive oil. Repeated topical treatment of DNCB gel resulted in prophylactic effect against lethal infection with herpes simplex virus type 1 (HSV-1). In mice repeatedly treated with DNCB gel and infected with HSV, a significant increase in serum IFN-γ was observed. These results suggest that topical DNCB functions as a potent immunomodulator, activating anti-viral defense mechanisms.