Direct cytocidal effect of galectin-9 localized on collagen matrices on human immune cell lines.
BACKGROUND
There is a continuous demand for new immunosuppressive agents for organ transplantation. Galectin-9, a member of the galactoside-binding animal lectin family, has been shown to suppress pathogenic T-cell responses in autoimmune disease models and experimental allograft transplantation. In this study, an attempt has been made to develop new collagen matrices, which can cause local, contact-dependent immune suppression, using galectin-9 and collagen-binding galectin-9 fusion proteins as active ingredients.


METHODS
Galectin-9 and galectin-9 fusion proteins having collagen-binding domains (CBDs) derived from bacterial collagenases and a collagen-binding peptide (CBP) were tested for their ability to bind to collagen matrices, and to induce Jurkat cell death in solution and in the collagen-bound state.


RESULTS
Galectin-9-CBD fusion proteins exhibited collagen-binding activity comparable to or lower than that of the respective CBDs, while their cytocidal activity toward Jurkat cells in solution was 80~10% that of galectin-9. Galectin-9 itself exhibited oligosaccharide-dependent collagen-binding activity. The growth of Jurkat cells cultured on collagen membranes treated with galectin-9 was inhibited by~90%. The effect was dependent on direct cell-to-membrane contact. Galectin-9-CBD/CBP fusion proteins bound to collagen membranes via CBD/CBP moieties showed a low or negligible effect on Jurkat cell growth.


CONCLUSIONS
Among the proteins tested, galectin-9 exhibited the highest cytocidal effect on Jurkat cells in the collagen-bound state. The effect was not due to galectin-9 released into the culture medium but was dependent on direct cell-to-membrane contact.


CONCLUSIONS
The study demonstrates the possible use of galectin-9-modified collagen matrices for local, contact-dependent immune suppression in transplantation.
Division of Research Instrument and Equipment, Life Science Research Center, Kagawa University, Kagawa, Japan.
Youko
Y
Fukata
Division of Research Instrument and Equipment, Life Science Research Center, Kagawa University, Kagawa, Japan.
Aiko
A
Itoh
Department of Endocrinology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Yasuhiro
Y
Nonaka
Department of Endocrinology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Takashi
T
Ogawa
Department of Endocrinology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Takanori
T
Nakamura
Department of Bacteriology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
Osamu
O
Matsushita
Division of Research Instrument and Equipment, Life Science Research Center, Kagawa University, Kagawa, Japan. Electronic address: nnishi@med.kagawa-u.ac.jp.
Nozomu
N
Nishi
D001665:Binding Sites; D049109:Cell Proliferation / Q000187:drug effects; D003094:Collagen / Q000378:metabolism*; D037161:Galectins / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D019169:Jurkat Cells; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000494:pharmacology
D037161:Galectins; D007166:Immunosuppressive Agents; C105032:LGALS9 protein, human; D011993:Recombinant Fusion Proteins; D003094:Collagen
Collagen; Collagen-binding domain; Galectin; Immune suppression