Impaired B cell terminal differentiation in B cell-specific knockout mice of cell death-defying factor anamorsin

Anamorsin (AM) is an anti-apoptotic molecule cloned by us as a molecule that confers resistance against apoptosis induced by growth factor deprivation. AM-deficient mice are embryonic lethal, which impedes detailed analyses of the roles of AM in various types of adult cells. To overcome the embryonic lethality, we generated AM conditional knockout (AM(flox/flox)) mice and cell type-specific genetic modification became possible using the Cre-loxP system. CD19-Cre/AM(flox/flox) mice with AM deleted specifically in CD19 thorn B cells exhibited less B220 thorn B cells in their spleen, peripheral blood, and lymph node compared with control CD19-Cre mice. Using flow cytometry to categorize bone marrow and spleen cells into B cell subsets, we observed significantly less follicular type I cells, which are the most mature follicular B cells, compared with control CD19-Cre mice. These data suggest that AM has an important role in the generation of mature B cells.(c) 2022 Published by Elsevier Inc.

Automated summary

Anamorsin (AM) is a cloned molecule that confers resistance against apoptosis induced by growth factor deprivation. Conditional knockout of AM in mice showed its important role in the generation of mature B cells.