Soluble mouse B7-H3 down-regulates dendritic cell stimulatory capacity to allogenic T cell proliferation and production of IL-2 and IFN-gamma.
B7-H3 is a recently identified member of the B7 gene family. Its ubiquitous expression in both lymphoid and nonlymphoid tissues suggests that it could play an important role in the maintenance of self-tolerance. However, the exact function of B7-H3 is still elusive. The purpose of current study is to demonstrate the possible function of soluble mouse B7-H3 for prevention of DC-mediated T cell activation. For this purpose, we established a soluble mouse B7-H3 fusion protein (mB7h3-hIg) eukaryotic expression vector (pmB7h3-hIg) with a C-terminal human IgG1 Fc. A C57BL/6 (B6)-derived dendritic cell line (DC2.4 cells) was used for the establishment of stable transfectants for generation of soluble mB7h3-hIg. Ectopic mB7h3-hIg expression was confirmed by RT-PCR, Western blot and ELISA analyses. A 49.7 kD protein was detected by Western blot from DC2.4 cells transfected with pmB7h3-hIg. It was found that soluble mB7h3-hIg expression has no effect on cell cycling and apoptosis and the expression of CD80 and CD86 of the DC2.4 cells. However, ectopic soluble mB7h3-hIg expression was found to significantly affect the allo-stimulatory capability for DC2.4 cells. DC2.4 cells expressing soluble mB7h3-hIg showed a significant reduced allo-stimulatory capability as compared with the controls determined by MLC. Further studies revealed that soluble mB7h3-hIg could also inhibit IL-2 and IFN-gamma production of allogenic T cells. These results suggested a great potential of soluble B7-H3 for treatment of graft rejection and autoimmume disease.
Xu
Junfa
J
Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
Huang
Baojun
B
Xiong
Ping
P
Feng
Wei
W
Xu
Yong
Y
Fang
Min
M
Zheng
Fang
F
Gong
Feili
F
D000818:Animals; D015703:Antigens, CD; D060887:B7 Antigens; D018122:B7-1 Antigen / Q000235:genetics; D002453:Cell Cycle / Q000276:immunology; D049109:Cell Proliferation; D003001:Cloning, Molecular; D018920:Coculture Techniques; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology*; D015536:Down-Regulation; D005822:Genetic Vectors; D006801:Humans; D007074:Immunoglobulin G / Q000235:genetics; D007371:Interferon-gamma / Q000378:metabolism*; D007376:Interleukin-2 / Q000378:metabolism*; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D016133:Polymerase Chain Reaction; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics*; D012995:Solubility; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*
D015703:Antigens, CD; D060887:B7 Antigens; D018122:B7-1 Antigen; C423237:CD276 protein, human; C486038:Cd276 protein, mouse; D016207:Cytokines; D007074:Immunoglobulin G; D007376:Interleukin-2; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; D007371:Interferon-gamma