Fig. 3.

Fusions involving CD28. A) Scheme of CD28-CTLA4 and CD28-ICOS fusions. Fusion of the C-terminal domain of CD28 and the N-terminal domain of CTLA-4 or ICOS may interact with CD80 or CD86 on ATLL cells or stromal cells, and convert the CTLA-4- or ICOS-mediated signal to a CD28-mediated co-stimulatory signal. B) ATLL cells strongly expressing CD28. C) CD80 is expressed on ATLL cells. D) Stromal cells positive for CD86.

CTLA-4, cytotoxic T-lymphocyte-associated protein 4; ICOS, inducible co-stimulator; ATLL, adult T-cell leukemia/lymphoma