Characterization of Sialic Acid-Binding Immunoglobulin-Type Lectins in Fish Reveals Teleost-Specific Structures and Expression Patterns

Abstract

The cellular glycocalyx of vertebrates is frequently decorated with sialic acid residues. These sialylated structures are recognized by sialic acid-binding immunoglobulin-type lectins (Siglecs) of immune cells, which modulate their responsiveness. Fifteen Siglecs are known to be expressed in humans, but only four Siglecs are regularly present in fish: Siglec1, CD22, myelin-associated glycoprotein (MAG), and Siglec15. While several studies have dealt with the physiological roles of these four Siglecs in mammals, little is known about Siglecs in fish. In the present manuscript, the expression landscapes of these Siglecs were determined in the two salmonid species Oncorhynchus mykiss and Coregonus maraena and in the percid fish Sander lucioperca. This gene-expression profiling revealed that the expression of MAG is not restricted to neuronal cells but is detectable in all analyzed blood cells, including erythrocytes. The teleostean MAG contains the inhibitory motif ITIM; therefore, an additional immunomodulatory function of MAG is likely to be present in fish. Besides MAG, Siglec1, CD22, and Siglec15 were also expressed in all analyzed blood cell populations. Interestingly, the expression profiles of genes encoding Siglecs and particular associated enzymes changed in a gene- and tissue-specific manner when Coregonus maraena was exposed to handling stress. Thus, the obtained data indicate once more that stress directly affects immune-associated processes.

Morphological and Molecular Features of Porcine Mesenchymal Stem Cells Derived From Different Types of Synovial Membrane, and Genetic Background of Cell Donors

“…The data analysis was performed using Kaluza software, ver. 1.2 (Beckman Coulter) ( Löhrke et al, 2010 ; Bornhöfft et al, 2020 ). All analyses were performed on samples from three donors for each synovial tissue source and each breed ( n = 3 independent biological replicate).…”

Enhancing the Anti-tumor Potency of a Novel Siglec-15 Antibody by Engineering its Fc-mediated Effector Functions

“…1 A), since the IgV domain and residue R143 of Siglec-15 are sufficient to mediate sialylated glycan binding. 8 , 33 To generate anti-Siglec-15 mAbs, mice immunized with high-affinity antibodies were selected for the cell fusion experiment. After 2 rounds of selection by ELISA, the best candidate was identified based on its high binding affinity for Siglec-15.…”

“…We generated a single substitution mutation, R143A, in Siglec-15 to facilitate mAb screening (Fig. 1A), since the IgV domain and residue R143 of Siglec-15 are sufficient to mediate sialylated glycan binding 8,33. To generate anti-Siglec-15 mAbs, mice immunized with high-affinity antibodies were selected for the cell fusion experiment.…”

An Update of Lectins from Marine Organisms: Characterization, Extraction Methodology, and Potential Biofunctional Applications

“…Given their ability to selectively recognize and bind the carbohydrate moiety of glycoconjugates, one of the most prominent physiological function of lectins in marine organisms is their role as potent defense molecules where they are involved in processes such as non-self-recognition, inflammation, opsonization, phagocytosis, encapsulation, and lysis of foreign cells [ 111 , 112 ]. The ability of lectins to trigger multiple immunological responses is essential for autoimmunity and management of infection in fish [ 63 , 72 , 86 , 113 ]. For instance, the lily type lectins, CsLTL-1 and CsLTL-2, are crucial immune genes in stripped murrel Channa striatus for selectively recognizing and eliminating pathogens by disrupting the cell membrane [ 113 , 114 ].…”

“…For instance, the lily type lectins, CsLTL-1 and CsLTL-2, are crucial immune genes in stripped murrel Channa striatus for selectively recognizing and eliminating pathogens by disrupting the cell membrane [ 113 , 114 ]. Recently, sialic acid-binding immunoglobulin-type lectins (Siglec1, CD22, myelin-associated glycoprotein (MAG), and Siglec15) in pikeperch ( Sander lucioperca ), rainbow trout ( Oncorhynchus mykiss ) and maraena whitefish ( Coregonus maraena ) influenced the cellular reactivity against damage-associated molecular patterns (DAMPs) [ 63 ]. Brinchmann et al [ 115 ] reported that fish mucosal lectins could trigger agglutination, inhibition of bacterial chemotaxis, endocytosis, phagocytosis, as well as inhibition of pathogens.…”