Mice homozygous for the beige-J spontaneous mutation (Lystbg-J) are identical to the original beige mutation (Lystbg). The phenotype closely resembles Chediak-Higashi disease in man and similar conditions in mink and cattle. Abnormal giant lysosomal granules occur in all tissues with granule-containing cells, including granulocytes, lymphocytes, cells of the liver, kidney, central nervous system, pancreas, and thyroid, and the ducts of most glands; in type II pneumocytes; in mast cells; and in retinal pigment epithelium. Granulocytes from beige homozygous mutant mice show defective chemotaxis and reduced bactericidal activity. Beige mice are more susceptible than controls to pneumonitis and to various viral, bacterial, and parasitic infections. Natural killer (NK) cells from beige mice exhibit decreased endogenous cytotoxic activity. Beige mice also have a defective cytotoxic T-cell and cytotoxic antibody response to allogeneic tumor cells. Syngeneic tumor cells grow better in beige mice than in littermate controls, an effect thought to be due to the deficiency of NK cells. Beige mice have platelet storage pool deficiency, leading to a prolonged bleeding time. The immunodeficiency of beige mutant mice has been used, especially in combination with the scid mutation (Prkdcscid), in tissue graft and disease studies.
