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J Immunol. Interactions of alpha-, beta-, and theta-defensins with influenza A virus and surfactant protein

Giuseppe

Emeritus
J Immunol. 2009 Jun 15;182(12):7878-87.

Interactions of alpha-, beta-, and theta-defensins with influenza A virus and surfactant protein

D. Doss M, White MR, Tecle T, Gantz D, Crouch EC, Jung G, Ruchala P, Waring AJ, Lehrer RI, Hartshorn KL. - Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA.


We have reported that the alpha-defensins human neutrophil peptides (HNP)-1 and HNP-2 neutralize and aggregate influenza A virus (IAV) and promote uptake of IAV by neutrophils. These alpha-defensins were also shown to bind to surfactant protein (SP)-D and reduce its antiviral activity.

In this study, we examined retrocyclin (RC)1 and RC2, humanized versions of the antiviral theta-defensins found in the leukocytes of certain nonhuman primates.

RC1 was just as effective as HNP-1-3 in neutralizing IAV, and RC2 and RC101 (an analog of RC1) were more effective. In contrast, human beta-defensins (HBDs) showed less neutralizing activity. Human defensins 5 and 6 (mainly produced by intestinal Paneth cells) had viral neutralizing activity similar to HNP-1-3. Like HNP-1-3, RCs induced viral aggregation and promoted the uptake of IAV by neutrophils.

We used surface plasmon resonance to evaluate binding of defensins to SP-D. HBDs, HD6, and HNP-4 bound minimally to SP-D. HNP-1-3 and RCs bound SP-D with high affinity; however, unlike HNP-1 and HNP-2, RCs did not inhibit SP-D antiviral activity. HBDs also did not inhibit antiviral activity of SP-D.

Given their strong neutralizing activity and compatibility with SP-D, RCs may provide attractive prototypes for designing therapeutics that can prevent or treat respiratory infections caused by IAV.

PMID: 19494312 [PubMed - in process]
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