SUMMARY
Early embryo aggregation derived mouse chimaeras have proven an extremely valuable tool to study development of disease processes. In this respect chimaeras prove a unique opportunity to study the interaction between cells genetically predestined to become diseased and a normal cell population within the same animal. In this situation chimaeras can be studied in view of possible ‘correction’ of the disease by the provision of a population of normal host cells and/or their products. Various host deficiency states including classic immune deficiency, potentially ‘deficient’ anaemias and tumours have been studied–the subject of the review here.