Naive CD4+ T cells carrying a TLR2 agonist overcome TGF-b–mediated tumor immune evasion
TLRs promote host defense through recognizing pathogenassociated
molecular patterns released by microorganisms
(1). TLR activation initiates potent inflammatory cytokine
production and dendritic cell activation that drive the expansion
and differentiation of Ag-specific T cells. These observations have
led to the clinical use of TLR agonists to promote antitumor responses.
These include the use of the TLR7 agonist imiquimod
and live preparations of Mycobacterium bovis bacillus of the
Calmette-Gue´rin strain to treat superficial skin and bladder carcinomas,
respectively (2, 3). However, TLR agonist therapy has
been largely restricted to mucosal lesions because of potential
systemic toxicity (4).
Although most studies have