Specific recognition of Leishmania major poly-beta-galactosyl epitopes by galectin-9: possible implication of galectin-9 in interaction between L. major and host cells.
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-beta-galactosyl epitope (Galbeta1-3)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 beta-galactoside-binding protein, galectin-3, can distinguish L. major from the other species through its binding to the poly-beta-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-beta-galactosyllactose revealed that the galectin-9 affinity for polygalactose was enhanced in proportion to the number of Galbeta1-3 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.
Pelletier
Isabelle
I
Glycobiology Laboratory, Research Centre for Infectious Diseases, Laval University Medical Centre, Centre Hospitalier Universitaire de Québec, Québec G1V 4G2, Canada.
Hashidate
Tomomi
T
Urashima
Tadasu
T
Nishi
Nozomu
N
Nakamura
Takanori
T
Futai
Masamitsu
M
Arata
Yoichiro
Y
Kasai
Ken--chi
K-
Hirashima
Mitsuomi
M
Hirabayashi
Jun
J
Sato
Sachiko
S
D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000276:immunology*; D002240:Carbohydrate Sequence; D004175:Diptera / Q000469:parasitology; D000939:Epitopes / Q000276:immunology; D005685:Galactans / Q000737:chemistry / Q000276:immunology*; D037161:Galectins / Q000276:immunology*; D006790:Host-Parasite Interactions; D006801:Humans; D007700:Kinetics; D007893:Leishmania donovani / Q000276:immunology; D018320:Leishmania major / Q000276:immunology*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry; D011994:Recombinant Proteins / Q000276:immunology
D000953:Antigens, Protozoan; D000939:Epitopes; D005685:Galactans; D037161:Galectins; C105032:LGALS9 protein, human; D009844:Oligosaccharides; D011994:Recombinant Proteins