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