Fibronectin maintains NK-cell survival via CD11b. (A) The expression of CD11b on NK cells isolated from mouse splenocytes and cultured in vitro at the indicated times is shown. (B) Three subsets of splenic NK cells were sorted according to the expression of CD11b using MoFlo sorting system and cultured in the presence of fibronectin, and then viability was detected 24 hours later. (C) Sorted mouse NK cells were precultured with or without the neutralizing anti-CD11b antibody, then cultured in the presence of fibronectin and the viability was detected 24 hours later. Isotype indicates isotype control for antibody to CD11b. (D) NK cells sorted from CD11b^−/− mice or littermate control were cultured in the presence of fibronectin and then collected, fixed, washed immediately at the indicated times, and labeled with antifibronectin antibody. The fibronectin bound to the surface of NK cells was tested by FACS. Data are shown as 1 typical result from 3 independent experiments with similar results or as mean ± SD of 3 independent experiments. *P < .05.