LPS response in vivo. (A) CSF1^m/m and CSF1^h/m mice were engrafted with human CD34⁺ cells, and 12 weeks after transplantation LPS was injected intraperitoneally. Forty-eight hours later mice were killed and the frequencies of human CD45⁺CD14⁺CD33⁺ cells in the spleen were determined. PBS-injected mice served as controls. Each symbol represents an individual mouse; horizontal bars indicate the mean values. (B-C) CSF1^m/m and CSF1^h/m mice were engrafted with human CD34⁺ cells, and 12 weeks after transplantation LPS was injected intraperitoneally. Six hours later mice were bled and the serum levels of human (right) and mouse (left) IL-6 and TNFα were quantified through ELISA. PBS-injected mice served as controls. Shown are the mean values of triplicate samples. Error bars indicate ± SEM.