Studies on beige-nude mice with low natural killer cell activity. 1. Introduction of the bg gene into nude mice and the characteristics of beige-nude mice.

To improve the take-rate of human tumours in nude mice, a nude mouse strain with the bg gene was established. The introduction of the bg gene was confirmed by examination of giant granules of blood neutrophils. The genetic profile of beige-nude mice was the same as that of the C57BL/6 strain according to genetic screening. The natural killer cell activity in the beige-nude mice was much lower than that in ordinary nude mice but slightly higher than that in beige mice. The reproductivity of beige-nude mice was as high as that of ordinary nude mice.