IMMUNOLOGICAL ABNORMALITIES EXHIBITED IN IL-7 TRANSGENIC MICE WITH DERMATITIS

Interleukin (IL)-7 transgenic mice, which we established previously, d eveloped severe dermatitis characterized by massive infiltration of ga mma delta T cells in the dermal lesion. To fully understand the pathol ogy of this intriguing skin disease, we examined several immunologic f eatures of dermis infiltrating lymphocytes from the lesional skin of I L-7 transgenic mice. We observed a moderate response to mitogens, a po or response to alloantigens, and the absence of cytotoxic activities t o several tumor cell lines and skin derived cells regardless of the pr esence of IL-2 or IL-7., On the other hand, dermis infiltrating lympho cytes could proliferate with exogenous IL-2 and IL-7., Moreover, rever se transcriptase polymerase chain reaction and fluorescence activated cell sorter analysis revealed that dermis infiltrating lymphocytes exp ressed various cytokines including IL-4 and IL-7, and several activati on markers for T cells (CD44, CD69, IL-2R alpha), in addition to IL-7R alpha., In the sera of the affected mice, hyper epsilon-globulinemia was observed. These findings suggested that dermis infiltrating lympho cytes proliferated in an activated state in the skin lesion in an auto crine and/or paracrine manner and produced Th2 type cytokines that mig ht evoke immunologic abnormalities, This study and previous findings s uggest that IL-7 transgenic mouse with dermatitis offer the potential of serving as a useful tool for investigating the immunologic role of cutaneous gamma delta T cells, especially their participation in IgE p roduction in vivo.