Molecular characterization of human 4Ig-B7-H3, a member of the B7 family with four Ig-like domains.
In an effort to characterize molecules with immunoregulatory potential, we raised mAbs to human dendritic cells. We selected an Ab that recognizes a molecule that is induced on monocytes differentiated in vitro toward dendritic cells. Retroviral expression cloning identified this molecule as B7-H3, a member of the B7 family described recently. In contrast to an earlier report, in which B7-H3 was described as a molecule consisting of two Ig-like domains, our cDNA encoded a type I membrane protein with four Ig-like domains, and the molecule identified by us was therefore named 4Ig-B7-H3. mRNA analysis as well as Western blotting experiments performed by us did not reveal evidence for a small B7-H3. B7-H3 is not expressed on peripheral blood lymphocytes, monocytes, or granulocytes. Upon in vitro stimulation, the expression of B7-H3 is induced on T cells, B cells, and NK cells. A number of different approaches were used to investigate the function of human B7-H3. In contrast to an earlier report, our data do not support a costimulatory role of B7-H3 in anti-CD3-mediated activation of the TCR-complex resulting in T cell proliferation and IFN-gamma production.
Steinberger
Peter
P
Institute of Immunology, University of Vienna Medical School, Vienna, Austria. peter.steinberger@univie.ac.at
Majdic
Otto
O
Derdak
Sophia V
SV
Pfistershammer
Katharina
K
Kirchberger
Stefanie
S
Klauser
Christoph
C
Zlabinger
Gerhard
G
Pickl
Winfried F
WF
Stöckl
Johannes
J
Knapp
Walter
W
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000937:Antigen-Antibody Reactions; D015703:Antigens, CD; D060887:B7 Antigens; D018122:B7-1 Antigen / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D017252:CD3 Complex / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D002460:Cell Line; D003001:Cloning, Molecular / Q000379:methods; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D007136:Immunoglobulins / Q000737:chemistry*; D008024:Ligands; D008213:Lymphocyte Activation / Q000276:immunology; D021962:Membrane Microdomains / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009000:Monocytes / Q000166:cytology / Q000276:immunology; D005810:Multigene Family / Q000276:immunology*; D009928:Organ Specificity / Q000235:genetics / Q000276:immunology; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000032:analysis; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000502:physiology; D011971:Receptors, Immunologic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D060887:B7 Antigens; D018122:B7-1 Antigen; C423237:CD276 protein, human; D017252:CD3 Complex; D007136:Immunoglobulins; D008024:Ligands; D012333:RNA, Messenger; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D011971:Receptors, Immunologic