Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradox
Galectins are characterized by their binding affinity for ß-galactosides, a unique binding site sequence motif, and wide taxonomic distribution and structural conservation in vertebrates, invertebrates, protista, and fungi. Since their initial description, galectins were considered to bind...
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doaj-659f928da60b49aeba822d4d7398b2ff2020-11-24T22:38:08ZengFrontiers Media S.A.Frontiers in Immunology1664-32242012-07-01310.3389/fimmu.2012.0019928064Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradoxGerardo R. Vasta0Hafiz eAhmed1Mihai eNita-Lazar2Aditi eBanerjee3Marta ePasek4Surekha eShridhar5Surekha eShridhar6Prasun eGuha7José A Fernández-Robledo8University of Maryland School of Medicine, IMETUniversity of Maryland School of Medicine, IMETUniversity of Maryland School of Medicine, IMETUniversity of Maryland School of Medicine, IMETUniversity of Maryland School of Medicine, IMETUniversity of Maryland School of Medicine, IMETThe Community College of Baltimore CountyUniversity of Maryland School of Medicine, IMETUniversity of Maryland School of Medicine, IMETGalectins are characterized by their binding affinity for ß-galactosides, a unique binding site sequence motif, and wide taxonomic distribution and structural conservation in vertebrates, invertebrates, protista, and fungi. Since their initial description, galectins were considered to bind endogenous (self) glycans and mediate developmental processes and cancer. In the past few years, however, numerous studies have described the diverse effects of galectins on cells involved in both innate and adaptive immune responses, and the mechanistic aspects of their regulatory roles in immune homeostasis. More recently, however, evidence has accumulated to suggest that galectins also bind exogenous (non-self) glycans on the surface of potentially pathogenic microbes, parasites, and fungi, suggesting that galectins can function as pattern recognition receptors (PRRs) in innate immunity. Thus, a perplexing paradox arises by the fact that galectins also recognize lactosamine-containing glycans on the host cell surface during developmental processes and regulation of immune responses. According to the currently accepted model for non-self recognition, PRRs recognize pathogens via highly conserved microbial surface molecules of wide distribution such as LPS or peptidoglycan (pathogen-associated molecular patterns; PAMPs), which are absent in the host. Hence, this would not apply to galectins, which apparently bind similar self/non-self molecular patterns on host and microbial cells. This paradox underscores first, an oversimplification in the use of the PRR/PAMP terminology. Second, and most importantly, it reveals significant gaps in our knowledge about the diversity of the host galectin repertoire, and the subcellular targeting, localization, and secretion. Furthermore, our knowledge about the structural and biophysical aspects of their interactions with the host and microbial carbohydrate moieties is fragmentary, and warrants further investigation.http://journal.frontiersin.org/Journal/10.3389/fimmu.2012.00199/fullC-type lectingalectinglycan ligandsmicrobial recognitionself/non-self recognition |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Gerardo R. Vasta Hafiz eAhmed Mihai eNita-Lazar Aditi eBanerjee Marta ePasek Surekha eShridhar Surekha eShridhar Prasun eGuha José A Fernández-Robledo |
spellingShingle |
Gerardo R. Vasta Hafiz eAhmed Mihai eNita-Lazar Aditi eBanerjee Marta ePasek Surekha eShridhar Surekha eShridhar Prasun eGuha José A Fernández-Robledo Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradox Frontiers in Immunology C-type lectin galectin glycan ligands microbial recognition self/non-self recognition |
author_facet |
Gerardo R. Vasta Hafiz eAhmed Mihai eNita-Lazar Aditi eBanerjee Marta ePasek Surekha eShridhar Surekha eShridhar Prasun eGuha José A Fernández-Robledo |
author_sort |
Gerardo R. Vasta |
title |
Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradox |
title_short |
Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradox |
title_full |
Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradox |
title_fullStr |
Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradox |
title_full_unstemmed |
Galectins as self/non-self recognition receptors in innate and adaptive immunity: An unresolved paradox |
title_sort |
galectins as self/non-self recognition receptors in innate and adaptive immunity: an unresolved paradox |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Immunology |
issn |
1664-3224 |
publishDate |
2012-07-01 |
description |
Galectins are characterized by their binding affinity for ß-galactosides, a unique binding site sequence motif, and wide taxonomic distribution and structural conservation in vertebrates, invertebrates, protista, and fungi. Since their initial description, galectins were considered to bind endogenous (self) glycans and mediate developmental processes and cancer. In the past few years, however, numerous studies have described the diverse effects of galectins on cells involved in both innate and adaptive immune responses, and the mechanistic aspects of their regulatory roles in immune homeostasis. More recently, however, evidence has accumulated to suggest that galectins also bind exogenous (non-self) glycans on the surface of potentially pathogenic microbes, parasites, and fungi, suggesting that galectins can function as pattern recognition receptors (PRRs) in innate immunity. Thus, a perplexing paradox arises by the fact that galectins also recognize lactosamine-containing glycans on the host cell surface during developmental processes and regulation of immune responses. According to the currently accepted model for non-self recognition, PRRs recognize pathogens via highly conserved microbial surface molecules of wide distribution such as LPS or peptidoglycan (pathogen-associated molecular patterns; PAMPs), which are absent in the host. Hence, this would not apply to galectins, which apparently bind similar self/non-self molecular patterns on host and microbial cells. This paradox underscores first, an oversimplification in the use of the PRR/PAMP terminology. Second, and most importantly, it reveals significant gaps in our knowledge about the diversity of the host galectin repertoire, and the subcellular targeting, localization, and secretion. Furthermore, our knowledge about the structural and biophysical aspects of their interactions with the host and microbial carbohydrate moieties is fragmentary, and warrants further investigation. |
topic |
C-type lectin galectin glycan ligands microbial recognition self/non-self recognition |
url |
http://journal.frontiersin.org/Journal/10.3389/fimmu.2012.00199/full |
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