Figure 3: Ly-6B-expressing inflammatory macrophages (MØ) actively divide in situ.

(a) The plots show total inflammatory (Inf) MØ populations (left), Ly-6B⁺ cells (middle) and their Ly-6B⁻ counterparts (right) 72 h after the induction of peritonitis with 2 × 10⁶ zymosan particles. As previously reported, there is only limited evidence of proliferation in the total Inf MØ population (left and Davies et al.¹⁸). However, when subdivided based on Ly-6B expression there was a clear enrichment of cells in the S, G2 and M stages of cell cycle amongst the Ly-6B-expressing cells (middle) and notable lack of proliferating cells within the Ly-6B⁻ population (right). Data are derived from individual mice and are representative of at least 3 experiments with 6- to 7-week-old C57BL/6 female mice and typically 3–5 mice per experiment. (b) The levels of proliferation within the two populations of Inf MØ in the same experiment shown above (a) was measured by the proportion of cells with >2N DNA content (left), >2N DNA content with Ki67 expression (‘SG2/M’, middle), phospho-Histone H3⁺ phase of mitosis (‘pHH3⁺’; right). Data are expressed as mean±s.e.m. of 5 mice per group (7-week-old female C57BL/6) and is representative of at least three experiments. Data were analysed by a paired t-test, ***P<0.001.