Immune surveillance and natural resistance: an evaluation.

Concepts in tumour immunology are changing fundamentally. Around 1970 tumour immunology contained the following related concepts: Thousands of tumour cells arise de novo each day. Tumour cells are antigenic in their host. All these antigenic tumour cells are killed by a strong immune surveillance system. A more likely set of concepts looks as follows: Tumour cells do not arise frequently. Tumour cells may be antigenic or not. There is no need to postulate a very strong immune surveillance or natural resistance system. In this paper I am reviewing our present knowledge of immune surveillance and natural resistance. Only scanty information appears to be available. This information suggests that virally induced tumours are usually killed by cytotoxic T lymphocytes, and natural killer cells, whereas immune surveillance and natural resistance against other tumours may be quite weak.