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Siglec-5 and Siglec-14 are polymorphic paired receptors that modulate neutrophil and amnion signaling responses to group B Streptococcus.

Ali SR, Fong JJ, Carlin AF, Busch TD, Linden R, Angata T, Areschoug T, Parast M, Varki N, Murray J, Nizet V, Varki A - J. Exp. Med. (2014)

Bottom Line: GBS amnion immune activation was likewise influenced by the SIGLEC14- polymorphism.We provide initial evidence that the polymorphism could influence the risk of prematurity among human fetuses of mothers colonized with GBS.This first functionally proven example of a paired receptor system in the Siglec family has multiple implications for regulation of host immunity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, Department of Pediatrics, Department of Pathology, Department of Medicine, and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, Department of Pediatrics, Department of Pathology, Department of Medicine, and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, Department of Pediatrics, Department of Pathology, Department of Medicine, and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093.

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The Siglec-5/14 genotype influences human neutrophil responses to GBS. (A) Human neutrophils of the indicated genotypes were left uninfected or infected with GBS or GBSΔβ (MOI = 5), and bacterial survival at 40 min was assessed by CFU enumeration. (B) Sig-14+/+ neutrophils were pretreated with the indicated concentrations of anti–Siglec-14 antibody (Ab) for 15 min, followed by GBS infection as in A; after 40 min, bacterial survival was assayed by CFU enumeration. Data are representative of three independent experiments with one donor in each experiment. (C) Human neutrophils of the indicated genotypes were infected with FITC-labeled GBS or with GBSΔβ at 4°C, and then bacterial binding to neutrophils at the 20-min time point was analyzed by FACS. The graph depicts MFI of GFP fluorescence on neutrophils. (D–F) Human neutrophils of the indicated genotypes were left unstimulated or stimulated with LPS, and IL-8 (D), Siglec-5 (E), and Siglec-14 (F) mRNA were analyzed by Q-RT-PCR at 2 h. Results were normalized to the amount of GAPDH mRNA. Data in this figure are representative of two to four independent experiments with one to three different donors per genotype in each experiment. Results are means ± SD; *, P < 0.05, **, P < 0.01.
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fig3: The Siglec-5/14 genotype influences human neutrophil responses to GBS. (A) Human neutrophils of the indicated genotypes were left uninfected or infected with GBS or GBSΔβ (MOI = 5), and bacterial survival at 40 min was assessed by CFU enumeration. (B) Sig-14+/+ neutrophils were pretreated with the indicated concentrations of anti–Siglec-14 antibody (Ab) for 15 min, followed by GBS infection as in A; after 40 min, bacterial survival was assayed by CFU enumeration. Data are representative of three independent experiments with one donor in each experiment. (C) Human neutrophils of the indicated genotypes were infected with FITC-labeled GBS or with GBSΔβ at 4°C, and then bacterial binding to neutrophils at the 20-min time point was analyzed by FACS. The graph depicts MFI of GFP fluorescence on neutrophils. (D–F) Human neutrophils of the indicated genotypes were left unstimulated or stimulated with LPS, and IL-8 (D), Siglec-5 (E), and Siglec-14 (F) mRNA were analyzed by Q-RT-PCR at 2 h. Results were normalized to the amount of GAPDH mRNA. Data in this figure are representative of two to four independent experiments with one to three different donors per genotype in each experiment. Results are means ± SD; *, P < 0.05, **, P < 0.01.

Mentions: Neutrophils are the critical first line phagocytic cells in innate immune defense against invasive bacterial pathogens. Sig-14+/+ human neutrophils killed GBS more efficiently than those isolated from Sig-14−/− individuals (Fig. 3 A). The difference in killing of GBS and GBSΔβ in Sig-14+/+ neutrophils was not statistically significant, probably because of the offsetting effect of endogenous Siglec-5. To confirm that the reduced GBS killing by Sig-14−/− neutrophils reflects the absence of Siglec-14 by itself, the Siglec-14 activity of Sig-14+/+ neutrophils was disrupted using an antibody that specifically recognizes Siglec-14 but not Siglec-5 (Yamanaka et al., 2009). Anti–Siglec-14 antibody–treated neutrophils killed GBS less efficiently than neutrophils treated with an isotype control antibody in a dose-dependent manner (Fig. 3 B). These differences in cytokine release and killing do not reflect differential overall binding of GBS to the neutrophil surface, which was similar in Sig-14+/+ and Sig-14−/− neutrophils and dependent on β-protein expression (Fig. 3 C). Upon LPS challenge, neutrophils from human donors with the Sig-14+/+ genotype also produced significantly higher levels of IL-8 transcript than Sig-14−/− neutrophils (Fig. 3 D).


Siglec-5 and Siglec-14 are polymorphic paired receptors that modulate neutrophil and amnion signaling responses to group B Streptococcus.

Ali SR, Fong JJ, Carlin AF, Busch TD, Linden R, Angata T, Areschoug T, Parast M, Varki N, Murray J, Nizet V, Varki A - J. Exp. Med. (2014)

The Siglec-5/14 genotype influences human neutrophil responses to GBS. (A) Human neutrophils of the indicated genotypes were left uninfected or infected with GBS or GBSΔβ (MOI = 5), and bacterial survival at 40 min was assessed by CFU enumeration. (B) Sig-14+/+ neutrophils were pretreated with the indicated concentrations of anti–Siglec-14 antibody (Ab) for 15 min, followed by GBS infection as in A; after 40 min, bacterial survival was assayed by CFU enumeration. Data are representative of three independent experiments with one donor in each experiment. (C) Human neutrophils of the indicated genotypes were infected with FITC-labeled GBS or with GBSΔβ at 4°C, and then bacterial binding to neutrophils at the 20-min time point was analyzed by FACS. The graph depicts MFI of GFP fluorescence on neutrophils. (D–F) Human neutrophils of the indicated genotypes were left unstimulated or stimulated with LPS, and IL-8 (D), Siglec-5 (E), and Siglec-14 (F) mRNA were analyzed by Q-RT-PCR at 2 h. Results were normalized to the amount of GAPDH mRNA. Data in this figure are representative of two to four independent experiments with one to three different donors per genotype in each experiment. Results are means ± SD; *, P < 0.05, **, P < 0.01.
© Copyright Policy - openaccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4042635&req=5

fig3: The Siglec-5/14 genotype influences human neutrophil responses to GBS. (A) Human neutrophils of the indicated genotypes were left uninfected or infected with GBS or GBSΔβ (MOI = 5), and bacterial survival at 40 min was assessed by CFU enumeration. (B) Sig-14+/+ neutrophils were pretreated with the indicated concentrations of anti–Siglec-14 antibody (Ab) for 15 min, followed by GBS infection as in A; after 40 min, bacterial survival was assayed by CFU enumeration. Data are representative of three independent experiments with one donor in each experiment. (C) Human neutrophils of the indicated genotypes were infected with FITC-labeled GBS or with GBSΔβ at 4°C, and then bacterial binding to neutrophils at the 20-min time point was analyzed by FACS. The graph depicts MFI of GFP fluorescence on neutrophils. (D–F) Human neutrophils of the indicated genotypes were left unstimulated or stimulated with LPS, and IL-8 (D), Siglec-5 (E), and Siglec-14 (F) mRNA were analyzed by Q-RT-PCR at 2 h. Results were normalized to the amount of GAPDH mRNA. Data in this figure are representative of two to four independent experiments with one to three different donors per genotype in each experiment. Results are means ± SD; *, P < 0.05, **, P < 0.01.
Mentions: Neutrophils are the critical first line phagocytic cells in innate immune defense against invasive bacterial pathogens. Sig-14+/+ human neutrophils killed GBS more efficiently than those isolated from Sig-14−/− individuals (Fig. 3 A). The difference in killing of GBS and GBSΔβ in Sig-14+/+ neutrophils was not statistically significant, probably because of the offsetting effect of endogenous Siglec-5. To confirm that the reduced GBS killing by Sig-14−/− neutrophils reflects the absence of Siglec-14 by itself, the Siglec-14 activity of Sig-14+/+ neutrophils was disrupted using an antibody that specifically recognizes Siglec-14 but not Siglec-5 (Yamanaka et al., 2009). Anti–Siglec-14 antibody–treated neutrophils killed GBS less efficiently than neutrophils treated with an isotype control antibody in a dose-dependent manner (Fig. 3 B). These differences in cytokine release and killing do not reflect differential overall binding of GBS to the neutrophil surface, which was similar in Sig-14+/+ and Sig-14−/− neutrophils and dependent on β-protein expression (Fig. 3 C). Upon LPS challenge, neutrophils from human donors with the Sig-14+/+ genotype also produced significantly higher levels of IL-8 transcript than Sig-14−/− neutrophils (Fig. 3 D).

Bottom Line: GBS amnion immune activation was likewise influenced by the SIGLEC14- polymorphism.We provide initial evidence that the polymorphism could influence the risk of prematurity among human fetuses of mothers colonized with GBS.This first functionally proven example of a paired receptor system in the Siglec family has multiple implications for regulation of host immunity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, Department of Pediatrics, Department of Pathology, Department of Medicine, and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, Department of Pediatrics, Department of Pathology, Department of Medicine, and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, Department of Pediatrics, Department of Pathology, Department of Medicine, and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093.

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Related in: MedlinePlus