Activation of cytotoxic T cells by solid tumours

Authors: D E SPEIser P S Ohashi

Publish Date: 2014/02/06

Volume: 54, Issue: 3, Pages: 263-271

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Abstract

Tumourspecific cytotoxic T cells CTLs are among the bestdefined biological anticancer weapons Nevertheless they often fail to control tumour growth in vivo Many reasons for this have been evoked tumours may actively inhibit CTLs or may protect them selves from CTL recognition by various means However one does not necessarily need to postulate such active immune evasion mechanisms specifically acquired by tumour cells In this review we argue that the failure of immune protection is due to the intrinsic inability of tumours to activate an effective immune response and that many tumours are similar to normal issues in this respect It is striking to see that the majority of the socalled immune escape mechanisms are not specifically acquired by selected tumour cells but are common mechanisms shared between solid tumours and normal healthy tissues Immune responses are poor because tumour antigens do not efficiently localize to lymph follicles in lymphoid tissues and are not efficiently presented to CTLs in an immunogenic context The fact that tumours do not induce CTLs but are often susceptible to lymphocytemediated cytotoxicity indicates that more intensified immunization protocols should result in improved clinical outcome

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