Costimulation mediated by the CD28 molecule plays an important role in optimal activation of T cells. However, CD28-deficient mice can mount effective T cell-dependent immune responses, suggesting the existence of other costimulatory systems. In a search for other costimulatory molecules on T cells, we have developed a monoclonal antibody (mAb) that can costimulate T cells in the absence of antigen-presenting cells (APC). The molecule recognized by this mAb, 9D3, was found to be expressed on almost all mature T cells and to be a protein of approximately 24 kD molecular mass. By expression cloning, this molecule was identified as CD9, 9D3 (anti-CD9) synergized with suboptimal doses of anti-CD3 mAb in inducing proliferation by virgin T cells. Costimulation was induced by independent ligation of CD3 and CD9, suggesting that colocalization of these two molecules is not required for T cell activation. The costimulation by anti-CD9 was as potent as that by anti-CD28. Moreover, anti-CD9 costimulated in a CD28-independent way because anti-CD9 equally costimulated T cells from the CD28-deficient as well as wild-type mice. Thus, these results indicate that CD9 serves as a molecule on T cells that can deliver a potent CD28-independent costimulatory signal.
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August 01 1996
A role for CD9 molecules in T cell activation.
X G Tai,
X G Tai
Biomedical Research Center, Osaka University Medical School, Japan.
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Y Yashiro,
Y Yashiro
Biomedical Research Center, Osaka University Medical School, Japan.
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R Abe,
R Abe
Biomedical Research Center, Osaka University Medical School, Japan.
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K Toyooka,
K Toyooka
Biomedical Research Center, Osaka University Medical School, Japan.
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C R Wood,
C R Wood
Biomedical Research Center, Osaka University Medical School, Japan.
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J Morris,
J Morris
Biomedical Research Center, Osaka University Medical School, Japan.
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A Long,
A Long
Biomedical Research Center, Osaka University Medical School, Japan.
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S Ono,
S Ono
Biomedical Research Center, Osaka University Medical School, Japan.
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M Kobayashi,
M Kobayashi
Biomedical Research Center, Osaka University Medical School, Japan.
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T Hamaoka,
T Hamaoka
Biomedical Research Center, Osaka University Medical School, Japan.
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S Neben,
S Neben
Biomedical Research Center, Osaka University Medical School, Japan.
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H Fujiwara
H Fujiwara
Biomedical Research Center, Osaka University Medical School, Japan.
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X G Tai
Biomedical Research Center, Osaka University Medical School, Japan.
Y Yashiro
Biomedical Research Center, Osaka University Medical School, Japan.
R Abe
Biomedical Research Center, Osaka University Medical School, Japan.
K Toyooka
Biomedical Research Center, Osaka University Medical School, Japan.
C R Wood
Biomedical Research Center, Osaka University Medical School, Japan.
J Morris
Biomedical Research Center, Osaka University Medical School, Japan.
A Long
Biomedical Research Center, Osaka University Medical School, Japan.
S Ono
Biomedical Research Center, Osaka University Medical School, Japan.
M Kobayashi
Biomedical Research Center, Osaka University Medical School, Japan.
T Hamaoka
Biomedical Research Center, Osaka University Medical School, Japan.
S Neben
Biomedical Research Center, Osaka University Medical School, Japan.
H Fujiwara
Biomedical Research Center, Osaka University Medical School, Japan.
Online ISSN: 1540-9538
Print ISSN: 0022-1007
J Exp Med (1996) 184 (2): 753–758.
Citation
X G Tai, Y Yashiro, R Abe, K Toyooka, C R Wood, J Morris, A Long, S Ono, M Kobayashi, T Hamaoka, S Neben, H Fujiwara; A role for CD9 molecules in T cell activation.. J Exp Med 1 August 1996; 184 (2): 753–758. doi: https://doi.org/10.1084/jem.184.2.753
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