THE BEIGE MODEL IN STUDIES OF NATURAL RESISTANCE TO SYNGENEIC, SEMISYNGENEIC, AND PRIMARY TUMORS

Abstract

This chapter describes the Beige model in studies of natural resistance to syngeneic semisyngeneic and primary tumors. The concept of natural surveillance against tumors postulates that the immune system can recognize and eliminate neoplastic cells before they give rise to overt malignancies. The role of natural killer (NK) cells in this hypothetical defence is sometimes discussed in terms of spontaneous tumor incidence in various inbred strains of mice that show constant differences in their levels of NK activity. The chapter presents two different models where the effect of the bg mutation on natural resistance can be studied in mice with thymus deficiency. In the first approach, beige-nude mice were obtained through a breeding scheme. The bg mutation was found to cause a defect in NK function also in nude mice, although the homozygosity for the nu alleles had compensated partly for this by elevating the NK activity above the very low levels observed in beige mice without the nu defect. The data indicate that the mechanism responsible for resistance in + / bg mice which is defective in bg / bg mice is bone-marrow derived and does not require an intact thymus to develop.