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. 2007 Jun 11;204(6):1383–1393. doi: 10.1084/jem.20061205

Figure 8.

Figure 8.

Evaluation of the contribution of NKCC1 expression by hematopoietic and lung cells to LPS-elicited neutrophil recruitment. We first performed an experiment to determine whether a difference in neutrophil recruitment and localization would continue to be observed in mice exposed to lethal doses of irradiation. NKCC1−/− and NKCC1+/+ mice were lethally irradiated and reconstituted with genetically identical marrow (A). 6–8 wk after engraftment mice were challenged with LPS, the total cells in the BALF were enumerated, and the MPO content of the BAL and the lung was determined. As expected, we continued to observe an increase in the number of neutrophils present in the BAL, although no difference in the total number of cells recruited to the lung was apparent. To determine whether expression of NKCC1 by neutrophils contributes to the differential distribution of these cells, we generated a second cohort of mice. In this case, after irradiation, NKCC1−/− mice received marrow from wild-type animals (NKCC+/+→ NKCC−/−), whereas NKCC1+/+ mice received marrow from NKCC1−/− mice (NKCC−/−→ NKCC+/+) (B). Higher cell counts in the BALF and higher MPO levels in the cells collected by lavage corresponded with loss of NKCC1 expression in the recipient, not the donor marrow (NKCC+/+→ NKCC−/−, n = 4). Cell counts and MPO activity were significantly higher in these animals compared with wild-type animals in which the recipient expressed NKCC1 but was reconstituted with NKCC1−/− hematopoietic cells (NKCC−/−→ NKCC+/+, n = 6). Again, no difference was observed between the groups in MPO activity in the lung. All values are expressed as mean ± SEM. *, P < 0.05.