Molecular characterization of human 4Ig-B7-H3, a member of the B7 family with four Ig-like domains

J Immunol. 2004 Feb 15;172(4):2352-9. doi: 10.4049/jimmunol.172.4.2352.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal / metabolism
  • Antigen-Antibody Reactions
  • Antigens, CD
  • B7 Antigens
  • B7-1 Antigen / chemistry*
  • B7-1 Antigen / genetics
  • B7-1 Antigen / immunology*
  • Base Sequence
  • CD3 Complex / immunology
  • CD3 Complex / metabolism
  • CD3 Complex / physiology
  • Cell Line
  • Cloning, Molecular / methods
  • Dendritic Cells / immunology
  • Humans
  • Immunoglobulins / chemistry*
  • Ligands
  • Lymphocyte Activation / immunology
  • Membrane Microdomains / immunology
  • Membrane Microdomains / metabolism
  • Molecular Sequence Data
  • Molecular Weight
  • Monocytes / cytology
  • Monocytes / immunology
  • Multigene Family / immunology*
  • Organ Specificity / genetics
  • Organ Specificity / immunology
  • Protein Structure, Tertiary
  • RNA, Messenger / analysis
  • Receptor-CD3 Complex, Antigen, T-Cell / physiology
  • Receptors, Immunologic
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Signal Transduction / immunology
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism


  • Antibodies, Monoclonal
  • Antigens, CD
  • B7 Antigens
  • B7-1 Antigen
  • CD276 protein, human
  • CD3 Complex
  • Immunoglobulins
  • Ligands
  • RNA, Messenger
  • Receptor-CD3 Complex, Antigen, T-Cell
  • Receptors, Immunologic

Associated data

  • GENBANK/AJ583695