Galectins: a key intersection between glycobiology and immunology

Rabinovich, Gabriel A.; Riera, Clelia M.; Landa, Carlos; Sotomayor, Claudia Elena

doi:10.1590/s0100-879x1999000400002

Cited by 25 publications

(17 citation statements)

References 82 publications

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“…4,17 It has recently been suggested that Gal-1 triggers early upstream events in T cell physiology, such as generation of inositol-1,4,5-triphosphate and tyrosine phosphorylation of phospholipase Cg1. 31 21 These genes may act as a step in the chain of events that convert signals at the cell membrane to long-lasting responses that require gene activity.…”

Section: Discussionmentioning

confidence: 99%

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Molecular mechanisms implicated in galectin-1-induced apoptosis: activation of the AP-1 transcription factor and downregulation of Bcl-2

et al. 2000

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Galectins are emerging as a new class of bioactive molecules with specific immunomodulatory properties. Galectin-1 (Gal-1), a member of this family, has been shown to induce apoptosis of mature T cells and immature thymocytes. To gain insight into the intracellular signals transduced by Gal-1 upon binding to mature T cells, we investigated whether this protein triggered activation of the dimeric AP-1 transcription factor. A marked increase in the binding of nuclear extracts to synthetic oligonucleotides containing the AP-1 consensus sequence, could be detected by an electrophoretic mobility shift assay, when T cells were cultured for 30 min in the presence of Gal-1. This DNA-binding activity was preceded by a rapid increase in the levels of c-Jun mRNA, as determined by Northern blot analysis. Requirement of AP-1 for Gal-1-induced apoptosis was confirmed by the dosedependent reduction on the level of DNA fragmentation observed when cells were pre-treated with curcumin (an inhibitor of AP-1 activation) before exposure to Gal-1. Finally, evidence is also provided by Western blot analysis, showing that Gal-1 inhibits Concanavalin A (Con A) induction of Bcl-2 protein. Results presented in this study provide the first experimental evidence regarding AP-1 and Bcl-2 as targets of the signal transduction pathway triggered by Gal-1 and set the basis for a more in depth understanding of the molecular mechanisms of T-cell death regulation. Cell Death and Differentiation (2000) 7, 747 ± 753.

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Section: Discussionmentioning

confidence: 99%

“…4 Its presence has been localized within the central and peripheral immune compartment in thymic epithelial cells, 5 activated T cells 6,7 and activated macrophages. 8,9 It has also been found in immune privileged sites of the body such as placenta, 10,11 cornea 12 and testis.…”

Section: Introductionmentioning

confidence: 99%

Molecular mechanisms implicated in galectin-1-induced apoptosis: activation of the AP-1 transcription factor and downregulation of Bcl-2

et al. 2000

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“…Recent studies demonstrate that some galectins act as immunomodulators and cell adhesion modulators (25,(27)(28)(29)(30)(31)(32)(33)(34)(35). We recently found that galectin-3 binds to L. major through L. major-specific poly-␤-galactosyl epitope (Gal␤1-3) n (16).…”

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confidence: 99%

Specific Recognition of Leishmania major Poly-β-galactosyl Epitopes by Galectin-9

Pelletier

Hashidate

Urashima

et al. 2003

Journal of Biological Chemistry

102

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Leishmania parasites are the causative agents of leishmaniasis, manifesting itself in a species-specific manner. The glycan epitopes on the parasite are suggested to be involved in the Leishmania pathogenesis. One of such established species-unique glycan structures is the poly-␤-galactosyl epitope (Gal␤1-3) n found on L. major, which can develop cutaneous infections with strong inflammatory responses. Interestingly, the polygalactosyl epitope is also suggested to be involved in the development of the parasites in its host vector, sand fly. Thus, the recognition of the galactosyl epitope by lectins expressed in host or sand fly should be implicated in the species-specific manifestations of leishmaniasis and in the parasite life cycle, respectively. We recently reported that one host ␤-galactoside-binding protein, galectin-3, can distinguish L. major from the other species through its binding to the poly-␤-galactosyl epitope, proposing a role for galectin-3 as an immunomodulator that could influence the L. major-specific immune responses in leishmaniasis. Here we report that galectin-9 can also recognize L. major by binding to the L. major-specific polygalactosyl epitope. Frontal affinity analysis with different lengths of poly-␤-galactosyllactose revealed that the galectin-9 affinity for polygalactose was enhanced in proportion to the number of Gal␤1-3 units present. Even though both galectins have comparable affinities toward the polygalactosyl epitopes, only galectin-9 can promote the interaction between L. major and macrophages, suggesting distinctive roles for the galectins in the L. major-specific development of leishmaniasis in the host.

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“…Another explanation is that viral coat proteins, instead of binding to the mucosa, could be trapped by cell membrane lectins such as galectins, widely distributed in the gastrointestinal tract of mammals (34), and then be internalized. Recent studies (16) have shown that the coat proteins of CPMV, closely related to CPSMV (28), are not glycosylated.…”

Section: Discussionmentioning

confidence: 99%

Immune response induced in mice oral immunization with cowpea severe mosaic virus

Florindo

Aragão

Silva

et al. 2002

Braz J Med Biol Res

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There is increasing interest in the immune response induced by plant viruses since these could be used as antigen-expressing systems in vaccination procedures. Cowpea severe mosaic virus (CPSMV), as a purified preparation (300 g of leaves, 2 weeks post-inoculation), or crude extract from cowpea (Vigna unguiculata) leaves infected with CPSMV both administered by gavage to Swiss mice induced a humoral immune response. Groups of 10 Swiss mice (2-month-old females) were immunized orally with 10 daily doses of either 50 µg viral capsid protein (boosters of 50 µg at days 21 and 35 after immunization) or 0.6 mg protein of the crude extract (boosters of 0.6 mg at days 21 and 35 after immunization). Anti-CPSMV antibodies were quantified by ELISA in pooled sera diluted at least 1:400 at days 7, 14, 21, 28, 35 and 42 after the 10th dose. IgG and IgA against CPSMV were produced systemically, but IgE was not detected. No synthesis of specific antibodies against the proteins of leaf extracts from V. unguiculata, infected or not with CPSMV, was detected. The use of CPSMV, a plant-infecting virus that apparently does not induce a pathogenic response in animals, induced a humoral and persistent (at least 6 months) immune response through the administration of low antigen doses by gavage. These results raise the possibility of using CPSMV either as a vector for the production of vaccines against animal pathogens or in quick and easy methods to produce specific antisera for viral diagnosis.

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Galectins: a key intersection between glycobiology and immunology

Cited by 25 publications

References 82 publications

Molecular mechanisms implicated in galectin-1-induced apoptosis: activation of the AP-1 transcription factor and downregulation of Bcl-2

Molecular mechanisms implicated in galectin-1-induced apoptosis: activation of the AP-1 transcription factor and downregulation of Bcl-2

Specific Recognition of Leishmania major Poly-β-galactosyl Epitopes by Galectin-9

Immune response induced in mice oral immunization with cowpea severe mosaic virus

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