Краткое описание

In this review, new data are interpreted that provide some answers to the question of why the immune system fails to respond to metastatic cancers. A function such as an element of the immune response is expected to be under the control of a gene. To find a gene, a mutant is required. Complex screens have been designed and used to detect mouse mutants resisting spread of transplantable tumors (in a spontaneous metastasis assay). Curiously, both mutants with increased and decreased resistance to spread of the tumor have been found. S-27 is a strongly resistant mutant linked to MHC; this mutation also affected some responses to Mycobacterium tuberculosis infection. A long sought link between malignant transformation and vaccination against mycobacterial diseases is discovered in this mutant. A search for a molecule responsible for effects of the S-27 mutation resulted in an unexpected finding. The S-27 mutant carries complex nucleotide alterations at the junction between the signal sequence and the sequences coding for the mature MHC class II A_β polypeptide chain. Antigen recognition region of the A_β molecule is not affected by this mutation. Some concepts developed during the course of this study are illustrated in Figures 1 to 4.