Defective DC Function
As key APC, DC play a central role in the induction of antitumour immune responses. They take up, process and present tumour-specific antigens and they are responsible for the activation of tumour-specific T cells.[111] DC infiltration is associated with an immune response against the tumour[112] and correlates with improved prognosis.[113] DC form clusters with T cells at the invasive margin of colorectal cancer stroma to promote T-cell activation for the generation of tumour-specific immunity[114]and infiltration has been linked with increased disease-free survival.[115]
However, patients with colorectal cancer have reduced peripheral DC numbers with reduced T-cell stimulation capability, with low levels of DC-associated antigens and impairment of DC activation within the cancer.[116,117] Tumour cells can inhibit DC differentiation[118] with increased precursor immature myeloid cells seen which are immunosuppressive, inhibiting T-cell proliferation and tumour-specific T-cell response.[119]
Aliment Pharmacol Ther. 2006;24(8):1163-1177. © 2006 Blackwell Publishing
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