An original colony of inbred athymic (nu/nu) mice on a BALB/c background was crossbred with outbred Swiss NIH mice to obtain a line of greater health, vigor, and fertility. Outbred nu/nu mice remain healthy and active under laboratory conditions up to 1 yr without resorting to antibiotic treatment, and can be raised successfully using either nu/nu or nu/+ mothers. The histopathology of these mice as well as their lymphoid surface markers and mitogen responsiveness confirms their "T-less" state. Unlike inbred athymic strains, they show no evidence of autoantibody formation and they have almost normal levels of IgA. They freely accept skin allografts throughout their life but do develop θ positivity and the ability to reject skin allografts after allogeneic thymic transplants. Of particular interest were elevated IgM levels and greatly elevated splenic IgM PFC background activities to a variety of synthetic chemical haptens. The cause of death of these mice was almost invariably due to extensive hepatic necrosis and fibrosis. In the total population at risk of over 1000 nu/nu mice, at least 150 of which were followed until 1 yr of age, not one spontaneous de novo cancer was noted.
ASJC Scopus subject areas
- Immunology and Allergy
- Pathology and Forensic Medicine