Propionibacterium acnes vaccination induces regulatory T cells and Th1 immune responses and improves mouse atopic dermatitis.

Atopic dermatitis (AD) is a chronic disease characterized by a polarized Th2 immune response. Propionibacterium acnes (P. acnes) has been shown to elicit strong Th1 immune responses. We hypothesized that the host immune response to P. acnes will prevent the development of AD. To demonstrate this hypothesis, we investigated the effect of P. acnes vaccination on AD that occurs in keratin 14/driven caspase-1 transgenic mouse. Vaccination with low dose of P. acnes successfully prevented clinical manifestations in the skin of AD mice associated with systemic and cutaneous increased expression of Th1-type cytokines but without suppression of Th2 cytokines. Interestingly, the numbers of IFN-γ(+) T cells, FoxP3(+) CD4(+) CD25(+) T cells (nTreg) and IL-10(+) T cells (Tr1) were significantly increased in the spleen. P. acnes vaccination has effects to alter the cytokine milieu and may be useful for the improvement of atopic symptom.