We are evaluating strategies to enhance the in vivo proliferation and
function of adoptively transferred antigen-specific T cells. Although
the CD28 costimulatory pathway is important for T cell activation and
proliferation, the expression of the ligands for CD28 is highly restri
cted. We have generated a chimeric receptor composed of signaling doma
ins of CD28 and the extracellular domain of CD2 which binds the widely
expressed ligand CD58. The CD2/CD28 chimeric receptor was introduced
into CTLL.2 cells via retrovirus infection and was shown to be express
ed on the cell surface. By monitoring early and late components of the
CD28 signaling pathway the chimeric receptor was demonstrated to trig
ger the CD28 pathway in response to CD2 cross-linking. The possible ut
ility of the CD2/CD28 chimeric receptor for adoptive immunotherapy is
discussed.