The Establishment of mutant mouse strain showing eosinophilia

Eosinophilia without IL-5 increasement

Abstract

Eosinophilia is a pathological condition characterized by increased eosinophils in tissues and peripheral blood. The type 2 immune response causes eosinophilia, and interleukin-5 (IL-5) secreted by T helper 2 (Th2) cells is essential for increasing eosinophils. However, it is unclear whether there is another mechanism for the increase in eosinophil other than IL-5 upregulation.

The present study found high eosinophils in the ICR mice and established inbred mice with hypereosinophilia, named “Yama mouse”, through brother-sister mating.

The eosinophils in the peripheral blood of 6-week-old Yama mice were 30-fold higher than those in ICR mice, and Yama mice did not have visible lesions. The IL-5 expression had no significant difference in the spleen, mesenteric lymph nodes, or bone marrow of ICR and Yama mice.

Yama mice revealed a mechanism for increased eosinophil counts other than that of IL-5 upregulation. Yama mice exhibit eosinophilia without artificial treatment; therefore, they are a good animal model for studying allergic diseases and regenerative medicine, in which eosinophils are important.