Surfactant proteins A and D inhibit the growth of Gram-negative bacteria by increasing membrane permeability
J. Clin. Invest. Huixing Wu, et al. 111:1589 doi:10.1172/JCI16889 [
Go to this article.]
Figure 7Inhibition of bacterial growth by SP-A and SP-D is independent of bacterial aggregation. Molten agarose was mixed with
E. coli K12 (
a and
b) or a clinical
E. coli isolate from a septic patient (
d), plated in Petri dishes, and allowed to cool. Wells were bored in the agar, and proteins (0.5 or 5.0 μg/well) were added for overnight incubation. (
a) BSA, lysozyme (Lys), rSP-A, or rSP-D was incubated with
E. coli K12. (
b)
E. coli K12 was incubated with 5 μg rSP-D (first two wells) or the protein-free filtrate (molecular weight cutoff of 10,000) from the 1-mg/ml rSP-D reagent (last two wells). (
c) Silver-stained SDS-PAGE gel of clinical
E. coli isolate showing slow- and fast-migrating species, consistent with smooth LPS phenotype. (
d) Clinical
E. coli isolate incubated with the same proteins as
E. coli K12, as well as hSP-A and ΔSP-D, a D203–F355 C-terminal fragment of recombinant mouse SP-D containing only the C-terminal domains.
