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Sialic acids siglec interaction: a unique strategy to circumvent innate immune response by pathogens.

Khatua B, Roy S, Mandal C - Indian J. Med. Res. (2013)

Bottom Line: They promote association with the immune cells through sialic acids-siglec dependent manner.Such an association plays an important role to subvert host's immunity.Particular attention has been focused on Pseudomonas aeruginosa (PA) and Leishmania donovani.

View Article: PubMed Central - PubMed

Affiliation: Cancer Biology & Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.

ABSTRACT
Sialic acids (Sias) are nine-carbon keto sugars primarily present on the terminal residue of cell surface glycans. Sialic acid binding immunoglobulins (Ig)-like lectins (siglecs) are generally expressed on various immune cells. They selectively recognize different linkage-specific sialic acids and undertake a variety of cellular functions. Many pathogens either synthesize or acquire sialic acids from the host. Sialylated pathogens generally use siglecs to manipulate the host immune response. The present review mainly deals with the newly developed information regarding mechanism of acquisition of sialic acids by pathogens and their biological relevance especially in the establishment of successful infection by impairing host innate immunity. The pathogens which are unable to synthesize sialic acids might adsorb these from the host as a way to engage the inhibitory siglecs. They promote association with the immune cells through sialic acids-siglec dependent manner. Such an association plays an important role to subvert host's immunity. Detailed investigation of these pathways has been discussed in this review. Particular attention has been focused on Pseudomonas aeruginosa (PA) and Leishmania donovani.

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Interaction of pathogens through linkage-specific sialic acids with different siglecs present on neutrophil and macrophages. The two pathogens namely L.donovani and P. aeruginosa contain α2,3 and α2,6 linked sialic acids on their surface. These linkage-specific sialic acids bind with siglec-1 and siglec-5 present on macrophages whereas siglec-5 and siglec-9 present on neutrophils.
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Figure 2: Interaction of pathogens through linkage-specific sialic acids with different siglecs present on neutrophil and macrophages. The two pathogens namely L.donovani and P. aeruginosa contain α2,3 and α2,6 linked sialic acids on their surface. These linkage-specific sialic acids bind with siglec-1 and siglec-5 present on macrophages whereas siglec-5 and siglec-9 present on neutrophils.

Mentions: Considering the vast microbial kingdom, assessment of the sialoglycan profile remains a relatively unexplored domain of microbial sialobiology. Although a few sialylated microorganisms have been reported (Table I)2829303132333435363738394041424344454647484950515253545556, sialylation status on PA remains untouched. Our group has recently demonstrated the status of sialic acids on PA by several analytical, biochemical and immunological methods2857. Sialic acid (Neu5Ac), its glycolyl derivative (Neu5Gc) and O-acetylated form (Neu5,9Ac2) on the surface of PA are detected by thin layer chromatography and fluorimetric-HPLC (Fig. 1A). The chromatogram exhibited well-resolved intense peaks corresponding to Neu5Ac, Neu5Gc and Neu5,9Ac2. Additionally, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF-MS) of purified Neu5Ac, Neu5Gc and Neu5,9Ac2 matched the expected signal having m/z at 448.7, 464.8 and 490.6, respectively confirming their occurrence on PA (Fig. 1B). Binding with Sambucus nigra agglutinin (SNA) and Maackia amurensis agglutinin (MAA) having specificity towards α2,6- and α2,3-linked sialic acids, respectively confirm the presence of linkage-specific sialic acids on PA5859 (Fig. 2). The bacterial membrane fraction showed stronger binding with SNA compared to Galanthus nivalis agglutinin, specific for terminal mannose (1,3), (1,6) and (1,2) mannose, Datura stramonium agglutinin, specific for galactose (1,4) N-acetyl glucosamine and peanut agglutinin, specific for galactose (1,3) N-acetyl galactosamine60. Further evidence for the presence of sialic acids is obtained using different siglecs where siglec-9 shows maximal binding with this bacteria33.


Sialic acids siglec interaction: a unique strategy to circumvent innate immune response by pathogens.

Khatua B, Roy S, Mandal C - Indian J. Med. Res. (2013)

Interaction of pathogens through linkage-specific sialic acids with different siglecs present on neutrophil and macrophages. The two pathogens namely L.donovani and P. aeruginosa contain α2,3 and α2,6 linked sialic acids on their surface. These linkage-specific sialic acids bind with siglec-1 and siglec-5 present on macrophages whereas siglec-5 and siglec-9 present on neutrophils.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928697&req=5

Figure 2: Interaction of pathogens through linkage-specific sialic acids with different siglecs present on neutrophil and macrophages. The two pathogens namely L.donovani and P. aeruginosa contain α2,3 and α2,6 linked sialic acids on their surface. These linkage-specific sialic acids bind with siglec-1 and siglec-5 present on macrophages whereas siglec-5 and siglec-9 present on neutrophils.
Mentions: Considering the vast microbial kingdom, assessment of the sialoglycan profile remains a relatively unexplored domain of microbial sialobiology. Although a few sialylated microorganisms have been reported (Table I)2829303132333435363738394041424344454647484950515253545556, sialylation status on PA remains untouched. Our group has recently demonstrated the status of sialic acids on PA by several analytical, biochemical and immunological methods2857. Sialic acid (Neu5Ac), its glycolyl derivative (Neu5Gc) and O-acetylated form (Neu5,9Ac2) on the surface of PA are detected by thin layer chromatography and fluorimetric-HPLC (Fig. 1A). The chromatogram exhibited well-resolved intense peaks corresponding to Neu5Ac, Neu5Gc and Neu5,9Ac2. Additionally, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF-MS) of purified Neu5Ac, Neu5Gc and Neu5,9Ac2 matched the expected signal having m/z at 448.7, 464.8 and 490.6, respectively confirming their occurrence on PA (Fig. 1B). Binding with Sambucus nigra agglutinin (SNA) and Maackia amurensis agglutinin (MAA) having specificity towards α2,6- and α2,3-linked sialic acids, respectively confirm the presence of linkage-specific sialic acids on PA5859 (Fig. 2). The bacterial membrane fraction showed stronger binding with SNA compared to Galanthus nivalis agglutinin, specific for terminal mannose (1,3), (1,6) and (1,2) mannose, Datura stramonium agglutinin, specific for galactose (1,4) N-acetyl glucosamine and peanut agglutinin, specific for galactose (1,3) N-acetyl galactosamine60. Further evidence for the presence of sialic acids is obtained using different siglecs where siglec-9 shows maximal binding with this bacteria33.

Bottom Line: They promote association with the immune cells through sialic acids-siglec dependent manner.Such an association plays an important role to subvert host's immunity.Particular attention has been focused on Pseudomonas aeruginosa (PA) and Leishmania donovani.

View Article: PubMed Central - PubMed

Affiliation: Cancer Biology & Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.

ABSTRACT
Sialic acids (Sias) are nine-carbon keto sugars primarily present on the terminal residue of cell surface glycans. Sialic acid binding immunoglobulins (Ig)-like lectins (siglecs) are generally expressed on various immune cells. They selectively recognize different linkage-specific sialic acids and undertake a variety of cellular functions. Many pathogens either synthesize or acquire sialic acids from the host. Sialylated pathogens generally use siglecs to manipulate the host immune response. The present review mainly deals with the newly developed information regarding mechanism of acquisition of sialic acids by pathogens and their biological relevance especially in the establishment of successful infection by impairing host innate immunity. The pathogens which are unable to synthesize sialic acids might adsorb these from the host as a way to engage the inhibitory siglecs. They promote association with the immune cells through sialic acids-siglec dependent manner. Such an association plays an important role to subvert host's immunity. Detailed investigation of these pathways has been discussed in this review. Particular attention has been focused on Pseudomonas aeruginosa (PA) and Leishmania donovani.

Show MeSH
Related in: MedlinePlus