Effect of PMNs derived MVs on bacterial growth. (A) Effect of PMNs (9 × 106/mL) and of b-MVs (derived from the same amount of PMNs) in time on growth of fresh, opsonized S aureus (9 × 107/mL). Points indicate mean ± SEM, n = 47. (B) MVs were collected from equal number of suspended PMNs incubated with opsonized or nonopsonized S aureus or from adherent PMNs incubated with opsonized S aureus. (C) MVs were collected after incubation of PMNs with the indicated agents (concentration and times are described in Figure 1C) and applied at equal protein concentration. (D) Effect of the same amount of b-MVs on the indicated, opsonized bacteria. (E) Antibacterial capacity of 9 × 106/mL PMNs (■) and of b-MVs (▴; derived from the same amount of PMNs) on opsonized (full symbols) and nonopsonized (empty symbols) S aureus. In panels B through E bacterial growth after 30 minutes incubation is shown; 100% represents the initial bacterial count (9 × 107/mL) that did not change in the absence of nutrients, but increased during the 30 minutes incubation period in the presence of nutrients. In panel B points indicate mean of protein concentration and of bacterial growth rate, ± SEM, n = 4; in panels C through E bars indicate mean ± SEM, n = 4; #P < .05.
