Blood, 15 October 2000, Vol. 96, No. 8, pp. 2808-2813
IMMUNOBIOLOGY
Costimulation of T cells by B7-H2, a B7-like molecule that
binds ICOS
Shengdian Wang,
Gefeng Zhu,
Andrei I. Chapoval,
Haidong Dong,
Koji Tamada,
Jian Ni, and
Lieping Chen
From the Department of Immunology, Mayo Graduate
and Medical Schools, Mayo Clinic, Rochester, MN; and Human Genome
Sciences, Inc, Rockville, MD.
This report describes a new human B7-like gene designated
B7-H2. Cell surface expression of B7-H2 protein is detected
in monocyte-derived immature dendritic cells. Soluble B7-H2 and
immunoglobulin (Ig) fusion protein, B7-H2Ig, binds activated but not
resting T cells and the binding is abrogated by inducible costimulator
Ig (ICOSIg), but not CTLA4Ig. In addition, ICOSIg stains Chinese
hamster ovary cells transfected with B7-H2 gene. By
suboptimal cross-linking of CD3, costimulation of T-cell proliferation
by B7-H2Ig is dose-dependent and correlates with secretion of
interleukin (IL)-2, whereas optimal CD3 ligation preferentially
stimulates IL-10 production. The results indicate that B7-H2 is a
putative ligand for the ICOS T-cell molecule.
