Phenotypes of B7-H4 × RAG-1 double KO mice (DKO). (A,B) Enlarged and increased weight of spleens from the DKO mice. Spleens were obtained from 6- to 8-week-old mice and the representatives of their appearance (A) and weights of average of 4 spleens (B) are shown. DKO indicates B7-H4 × RAG-1 double KO; RKO, RAG-1 KO; B7-H4 KO, B7-H4 KO mice in B6 background; and WT, normal B6. *P < .05. Error bars indicate SD (n = 3 mice). (C) Flow cytometric analysis of Gr-1⁺CD11b⁺ neutrophils in the absence of B7-H4. Cells were isolated from bone marrows, spleens, livers, and peripheral blood mononuclear cells (PBMCs) of indicated mice and stained with Gr-1 and CD11b mAb. Data were analyzed by flow cytometry.