Fibronectin supplements and LPS priming of PMN. Purified fibronectin was added to PBS (n = 5, •), adult fibronectin-depleted plasma (n = 5, ▿), or newborn fibronectin-depleted plasma (n = 5, ▾) and the preparations were used in LPS priming experiments. Results are expressed as CL units using lucigenin as the indicator for superoxide production by PMNs after fMLP triggering. Using multivariate repeated measures analysis of variance the overall effect of fibronectin dose was highly significant (P = .001). In addition, for each step increment of fibronectin 0-75, 75-150, and 150-300 significant increases were found (P = .002, P = .0001, and P = .008, respectively). This relationship was also significant for both the adult and newborn FN-depleted samples supplemented with fibronectin. Effect of untreated adult plasma (AD) and untreated newborn plasma (NB) on LPS priming are shown on right of the figure. *P < .05, increment in CL units for sample supplemented with 0 to 300 μg/mL fibronectin versus increment in CL units for PBS supplemented with 0 to 300 μg/mL fibronectin. +P < .05 priming activity (CL units) of newborn FN-depleted plasma reconstituted with 300 μg of fibronectin compared with that of adult plasma. ▿P < .05 priming activity (CL units) of adult plasma compared with that of adult FN-depleted plasma.