| Ligand name (alternative
names) |
%identity of extracellular
domain |
Protein expression
pattern in lymphoid cells |
mRNA expression in
non-lymphoid tissue or
cells |
Receptor |
Function of ligandreceptor
interaction |
| B7-1 (CD80) |
100% |
Induced in T, B DCs and
monocytes |
Rare |
CD28
CTLA-4 |
Costimulation
Coinhibition |
| B7-2 (CD86) |
27% |
Constitutive and
upregulated upon
activation in B, DCs, and
monocytes; induced in T |
Rare |
CD28
CTLA-4 |
Costimulation
Coinhibition |
| ICOSL (B7h; B7RP-1; B7-
H2; GL-50) |
27% |
Constitutive in B, DCs,
macrophages, and a
subset of T |
Lung, liver, kidney, and
testes |
ICOS |
Costimulation |
| PD-L1 (B7-H1) |
25% |
Constitutive and
upregulated upon
activation in B, DCs, and
monocytes; induced T |
Placenta, heart, pancreas,
lung, liver, and tumor
cells (carcinomas and
melanomas) |
PD-1 |
Coinhibition |
| PD-L2 (B7-DC) |
23% |
Induced in DCs and
monocytes |
Heart, placenta, lung,
liver keratinocytes, and
epithelial cells |
PD-1 |
Coinhibition |
| B7-(B7S1; B7x) |
25% |
Induced in T, B, DCs and
monocytes |
Heart, kidney, testes, lung,
liver, pancreas, prostate,
colon, osteoblasts, and
tumor cells |
Unknown |
Coinhibition |
