Table 1.

Lectins extracted from different organisms and their biological functions.

Types of Organisms	Lectin Family	Specificity	Tissue Expression	Features/Functions	References
Turbot (Scophthalmus maximus L.)	RBL	l-rhamnose or d-galactose	Egg cortex and ovary cells	–Agglutinates Gram-positive and Gram-negative bacteria –Enhances phagocytosis	[27]
Purplish bifurcate mussel (Mytilisepta virgata)	RBL	Sevil, a glycan binding lectin	Mantles and gills	–Showed cytotoxic effects (apoptosis) against ovarian, breast, and colonial cancer cell line culture –Apoptosis against dog kidney cell line culture –Provides immune defense against infecting pathogens	[28]
Sea urchin (Anthocidaris crassispina)	RBL (SUEL-type)	d-Galactose	Eggs	–Expresses hemagglutination activity through the disulfide-linked homodimer of two subunits	[29]
Southern catfish (Silurus meridionalis)	RBL	l-rhamnose	Gill, barbel	–Contains two of the seven CRD (CRD3 and CRD5) described in animals –Involved in innate immunity	[30]
Nile tilapia (Oreochromis niloticus)	RBL	l-rhamnose	Liver, gills, intestines	–Contains four lectin genes with two tandem-repeated five CRD –Activates innate immune responses to infections	[31]
Catfish (Silurus asotus)	RBL	α-galactoside	Eggs	–Composed of 3 tandem-repeated domains which bind to globotriaosylceramide (Gb3) glycan (Gala1-4Galb1-4Glc) –Induces earlier apoptosis in Burkitt’s lymphoma cell lines –Enhances the effectiveness of anti-cancer drugs	[32,33,34]
Turbot (Scophthalmus maximus L.)	RBL	l-rhamnose	Egg, ovaries	–Composed two RBL with tandems repeated CRD5 of type IIIc RBL –Involved in turbot mucosal immunity	[27]
Chum salmon (Oncorhynchus keta)	RBL	l-rhamnose	Eggs	–Enhances intracellular Ca++ of Caco-2 cell monolayers	[35]
Shishamo smelt (Osmerus lanceolatus)	RBL	l-rhamnose	Eggs	–Exhibits two tandem-repeated domains –Binds to Raji cells through the Gb3 carbohydrate chain and induces cell death –Inhibits by melibiose	[34]
Bay scallop (Argopecten irradians)	CTL	Galactose	Muscle, gonad, hepatopancreas, mantle margine, and gill	–Play a crucial role in the innate immunity of bay scallop such as antimicrobial activity, non-self-recognition, and promotion nodule formation and phagocytosis –Provide strong immune response against Gram-positive and Gram-negative bacterial infection	[36]
Horsemussels (Modiolus kurilensis)	CTL	Glycan	Hemolymph	–Demonstrated antibacterial activities against Gram-positive and Gram-negative bacteria –Inhibits the human adenocarcinoma HeLa cells proliferation –Has immune function in M. kurilensis –Has pattern recognition receptors (PRR) and has interactions with Pathogen-Associated Molecular patterns (PAMPs) (e.g., mannan, PDG and LPS) –Growth inhibition of bacteria and shows agglutination activity –Potential for application in the field of biotechnology and biomedicine	[37]
Clam (Glycymeris yessoensis)	CTL	Peptidoglycan, LPS, β-1,3-glucan and mannan	Hemolymph	–Exhibited immune response of clam against bacterial attack –Served as PRR –Useful marker for understanding the immune system status of bivalves –Marker for studying environmental induced stress in mollusks –Synthesis of this molecule increased when animals were exposed to pathogens or environmental stresses	[38]
Kadal Shrimp (Metapenaeus dobsoni)	CTL	Glycan	Hemolymph	–Showed antibacterial activity against pathogenic Aeromonas hydrophila, Enterococcus fecalis and Streptococcus iniae challenged with Nile tilapia	[39]
Molluscan snail (Hemifusus pugilinus)	CTL	Mannose	Haemolymph	–Exhibited antibacterial and antibiofilm activity towards Gram-positive and Gram-negative bacteria –Showed antifungal activity against Aspergillus niger and A. flavus –Increased innate immune response	[40]
Manila clam (Venerupis philippinarum)	CTL	Glucan	Gill tissues and hepatopancreas	–Agglutinate Gram-positive and Gram-negative bacteria –Demonstrated prompt phagocytosis against non-self –Enhanced innate immune responses	[41]
Sea urchin (Pseudocentrotus depressus)	CTL	Mannose	Crushed body	–Agglutinate E. coli and Lactococcus garvieae –Act as defense molecules on the body surface of sea urchin	[42]
Sea urchin (Pseudocentrotus depressus)	CTL	Glycan	Tube feet	–Composed of five lectins, such as Griffonia simplicifolia lectin II (GSL II), wheat germ agglutinin (WGA), Solanum tuberosum lectin (STL), Lycopersicon esculentum lectin (LEL), and soybean agglutinin (SBA) –Could secret additives and provide additive power to the tube feet	[43]
Mud crab (Scylla paramamosain)	CTL	Glucan	Hemocytes, midgut, muscle, stomach, hapatopancreas, testis, ovaries, and heart	–Play a key role in immune-related genes and immunological parameters –Reduced the bacterial endotoxin level in vitro that renders to improve the survival rate of mud crab –Effective for mud crab aquaculture disease control	[44]
Brittle star (Ophioplocus japonicus)	CTL	Glucose/xylose	Whole body	–NS	[45]
Goldfish (Carassius auratus)	CTL	Mannose	Liver, spleen, kidney	–Calcium ion-dependent –Agglutinates rabbit erythrocytes and bacteria (E. coli and A. hydrophila, S. aureus) –Initiates innate immunity in the host	[46]
Turbot (Scophthalmus maximus) Black rockfish (Sebastes schlegelii) (SsLTL)	LTL	d-mannose	Skin, gill, and intestine	–Hydrophilic protein –Enhances hemagglutinating activity against fish and mice erythrocytes –Selectively binds to bacterial species including E. tarda and V. anguillarum	[47,48,49]
Giant prawn (Macrobrachium rosenbergii)	LTL	Mannose	Hemocytes, intestine, and hepatopancreas	–Inhibited the growth activities of microorganisms in vitro –Accelerated the bacterial clearance in vivo –Inhibited the virus replication in vivo that reduce the mortality of prawn	[50]
Sea bass (Dicentrarchus labrax L.)	FTL	Fucose-binding	Liver, larvae, eggs, intestine	–Embryo FBL exhibits MW of 34 kDa under reducing conditions but 30 kDa in the absence of B mercaptoethanol –Agglutinate erythrocytes	[51,52]
Striped beakfish (rock bream) (Oplegnathus fasciatus)	FTL	Fucose-binding	Intestines	–Modulates the expression of proteins related to viral budding and thrombin signaling (F2), which increase the viability of VHSV-infected cells	[53]
Striped Bass (Morone saxatilis)	FTL	Fucose-binding	Liver	–Two-tandem domains that exhibit CRS motif –Enhances innate immune responses	[54]
sea bass (Dicentrarchus labrax)	FTL	l-rhamnose	Liver and intestine	–Enhances phagocytosis	[55]
Steelhead trout (Oncorhynchus mykiss)	FTL	l-rhamnose	Eggs	–Exists in two forms: STL1 and STL2 with estimated MW of 84 and 68 kDa, respectively –STL1—noncovalently linked trimer of 31.4-kDa subunits –STL2—noncovalently linked trimer of 21.5-kDa subunits –Agglutinates rabbit erythrocytes	[56]
Sea bass (Dicentrarchus labrax)	FTL	l-fucose-binding	Intestine, liver	–Enhances immune defense responses in intestinal mucus and bloodstream –Upregulates gene expression and secretion of encoded proteins that are involved in both the innate and adaptive immune responses	[57]
Atlantic Salmon (Salmo salar)	Galectin	Glycans	Gill epithelial cell	–Two candidates: mannobiose and N-acetylgalactosamine (GalNAc) –Instant amoeba detachment –Block parasitic attachment	[58]
Striped snakehead (Channa striatus)	Galectin	Galactosidase	Liver	–Expression induced by epizootic ulcerative syndrome (EUS) causing pathogens such as Aphanomyces invadans –G4 peptide exhibits weak bactericidal activity against Vibrio harveyi –Relies on pentamer oligotryptophan (W5) at the C-terminal for its membrane disruption activity	[9]
Korean rose bitterling (Rhodeus uyekii)	Galectin	β-galactoside	Liver, brain, kidney, ovary, gills, spleen	–Upregulates by lipopolysaccharide –Triggers innate immunity	[59]
Turbot (Scophthalmus maximus L.)	Galectin	β-galactoside	Skin and brain	–Strong binding potentials to microbial ligands –Enhances immune response against infection	[60]
Euryhaline rotifers (Brachionus Plicatilis and Proales similis)	Galectins	Carbohydrate-binding domains with long N-terminal region (i.e., ~100 amino acids) β-galactosyl binding lectins		–C-type lectins- –Regulate innate immunity by enhancing microbial opsonization and melanization through prophenoloxidase enzyme activation –Activation of complement system –Serve as mate recognition pheromone –Galectins- –Assist cell adhesion, –Maintain cellular homeostasis –Help self/non-self and microbial recognition	[61]
Sea Hare (Aplysia kurodai)	GBL	d-galacturonic acid and d-galactose	Eggs	–Showed a moderate toxicity to Artemia nauplii –Apoptosis to cell death –Worked against the growth of erythroleukemia cells of human –Antifungal and antibacterial activities and involved in the defense of sea hare embryo –Suppressed the growth of the tumors, such as Ehrlich ascites carcinoma	[62]
Pikeperch (Sander lucioperca), rainbow trout (Oncorhynchus mykiss), and maraena whitefish (Coregonus maraena)	Siglecs (Siglec1, Siglec15, CD22, and myelin-associated glycoprotein (MAG))	Sialic-acid-binding	Head kidney, liver, gills, spleen, heart, and muscle	–MAG contains immunoreceptor tyrosine-based inhibitory motif (ITIM) –Some pathogens can express sialic acids which is identified by Siglecs –Fish associated with 4 types: Siglec1, CD22, myelin-associated glycoprotein (MAG) and Siglec 15 –Influences the cellular reactivity against damage-associated molecular patterns (DAMPs)	[63]
Marine sponge (Aplysina fulva)	AFL	Galactose	Crude extract	–Marine sponge showed interesting bioactivities such as antitumor, antiviral, and antibacterial activity –Mitogenicity, modulatory, and cytotoxicity activity on mammalian glutamate-gated ion channels –Reduce the biomass biofilm of the E. coli, Staphylococcus aureus, and S. epidermidis	[64]

Galactose binding lectin (GBL), rhamnose binding lectin (RBL), B-type Lectins (BTL), Lily type lectin (LTL), C-type lectin (CTL), F-type lectin (FTL), viral haemorrhagic septicaemia virus (BTL), mucin-binding lectin (AFL), molecular weight (MW), carbohydrate recognition domain (CRD), carbohydrate recognition sequence (CRS), viral hemorrhagic septicemia virus (VHSV), immunoglobulin-like lectin (IgTL), not reported (NR), not studied (NS).