A double recombinant adenovirus expressing the costimulatory molecule B7-1 (murine) and human IL-2 induces complete tumor regression in a murine breast adenocarcinoma model.

Tumors that express tumor-specific antigens can maintain growth in an immunocompetent organism. Current hypotheses tend toward T cell anergy as a key component for the inhibition of immunoreactivity against such tumors. Anergy is thought to occur from hyperactive stimulation of the TCR in the absence of costimulation (costimulation leads to proliferation via IL-2 production). Subcutaneous injection of transgenic polyoma middle T transformed …