Figure 3.

Early bacterial exposure of bone marrow cells is required to inhibit dentritic cell (DC) differentiation. Freshly isolated bone marrow cells were cultured with granulocyte–macrophage colony-stimulating factor for 7 days. Bacteria (1 : 1 colony-forming unit : cell) were added to cultures at the beginning of culture (D0) following 3 days culture in GM-CSF (D3) or following 5 day culture (D5). Control cells were not exposed to bacteria (control). Surface phenotype of cells harvested from cocultures on day 7 was analysed by flow cytometry for the expression of various DC markers. n ≥ 3. Significance is compared with control values. **P ≤ 0·01, ***P ≤ 0·001.