Xpr1 ^Lacz/Lacz mice lack FL macrophages. (A) Representative flow cytometry plots and frequencies (mean ± SD) of microglia (CX3CR1⁺CD206⁻) and BAMs (CX3CR1⁺CD206⁺) from brains of E16.5 Xpr1^+/+, Xpr1^LacZ/+, and Xpr1^LacZ/LacZ embryos (pre-gated on CD45⁺Ly6C⁻Ly6G⁻ cells). Each time point shows data from at least two independent experiments, n = 7–14 per group and time point. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple comparisons test. (B) Representative flow cytometry plots and frequencies (mean ± SD) of LC precursors (pre-LC) and Ly6C^hi monocytes (Mo) extracted from limb buds (E14.5) or skin (epidermis and dermis) of E16.5 Xpr1^+/+, Xpr1^LacZ/+, and Xpr1^LacZ/LacZ embryos (pre-gated on CD45⁺Ly6G⁻CD11b⁺ cells). Each time point shows data from at least two independent experiments, n = 5–9 per group and time point. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple comparisons test. (C and D) Representative flow cytometry plots, frequencies (mean ± SD) and total cell numbers (per mg tissue) (mean ± SD) of (C) macrophages (Macs) (pre-gated on CD45⁺Ly6G⁻Ly6C⁻ cells) and (D) Ly6C^hi monocytes (Mo) (pre-gated on CD45⁺Ly6G⁻F4/80⁻ cells) from livers of E16.5 Xpr1^+/+, Xpr1^LacZ/+, and Xpr1^LacZ/LacZ embryos. Two independent experiments for each time point, n = 5–16 for frequencies and n = 2–6 for total cell numbers. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple comparisons test. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001. ns, not significant.