Generation and phenotype of β2^TTT/AAA integrin knock-in mice. (A) Arrangement of the murine Itgb2 genomic locus (top), targeting vector (second from top), targeted Itgb2 allele after homologous recombination (second from bottom), and the constitutively expressed Itgb2 knock-in allele after Flp recombination (bottom). F3–Flp recombination target site. (B) The size of secondary lymphoid tissues (spleen, inguinal lymph nodes, and mesenteric lymph nodes) in 6- to 10-week-old WT and β2^TTT/AAA integrin knock-in (KI) homozygote mice, presented as cell number (N = 5 mice). (C) Proportions of B cells and CD4 and CD8 T cells in the spleen and inguinal lymph nodes of 6- to 10-week-old WT and KI mice (N = 3). (D) Circulating neutrophil numbers were identified by forward/side scatter profiles, with representative plots (left) and pooled data from 6 mice (right). (E) Gr-1 staining of blood samples to identify circulating neutrophils (N = 6 mice). (F) Splenic regulatory T cells were identified by intracellular Foxp3 staining (N = 6 mice). In all cases, Student t test was used to calculate significance values. NS, not significant. In all cases, mean ± SEM are presented.