Temporal recruitment of neutrophils and eosinophils to the skin in a murine model for onchocercal dermatitis

The parasitic helminth Onchocerca volvulus causes ocular onchocerciasis (ri ver blindness) and onchocercal skin disease. To understand the immunologic basis for early stage skin disease, we developed a model in which C57B1/6 m ice were immunized subcutaneously and injected intradermally (in the ear) w ith soluble O. volvulus antigens (OvAg). We found that ear thickness increa sed significantly after intradermal injection of OvAg and remained elevated fur at least 7 days. Dermatitis was dependent on prior immunization, and w as associated with an intense cellular infiltrate in the dermis. Neutrophil s were the predominant inflammatory cells in the dermis 12 hr after intrade rmal injection, with only occasional eosinophils present. Conversely, incre ased ear thickness at later time points was associated with eosinophils, an d neutrophils were only rarely detected. Both cell types were present at in termediate time points. These data indicate that recruitment of neutrophils and eosinophils to the skin is temporally regulated.