Editors' ChoiceInnate Immunity

Netting the Bad Guys

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Science Signaling  31 Jul 2012:
Vol. 5, Issue 235, pp. ec204
DOI: 10.1126/scisignal.2003440

Antimicrobial peptides are an evolutionarily conserved component of innate immunity in the intestine. One family, α-defensins, typically exerts their antimicrobial effects through microbicidal activity against bacteria. Humans express only two α-defensins, human defensin 5 (HD5) and HD6. HD5 exhibits bactericidal activity and plays a role in shaping the bacterial composition of the gut. HD6, on the other hand, does not show bactericidal activity and its function in the gut is unclear. Now, Chu et al. (see the Perspective by Ouellette and Selsted) show that HD6 protects against bacterial pathogens. Rather than killing them directly, HD6 binds to bacteria surface proteins and, through a process of self-assembly, forms fibrils and nanonets that ensnare invading bacterial pathogens.

H. Chu, M. Pazgier, G. Jung, S.-P. Nuccio, P. A. Castillo, M. F. de Jong, M. G. Winter, S. E. Winter, J. Wehkamp, B. Shen, N. H. Salzman, M. A. Underwood, R. M. Tsolis, G. M. Young, W. Lu, R. I. Lehrer, A. J. Bäumler, C. L. Bevins, Human α-defensin 6 promotes mucosal innate immunity through self-assembled peptide nanonets. Science 337, 477–481 (2012). [Abstract] [Full Text]

A. J. Ouellette, M. E. Selsted, HD6 defensin nanonets. Science 337, 420–421 (2012). [Abstract] [Full Text]