A new mutant hairless mouse with lymph node hyperplasia and late onset of autoimmune pathology.

Adult BALB/c male mice were injected with a single dose of ethyl nitroso urea (ENU; 250 mg/kg, i.p.) and mated to C57BL/6, DBA/2 and A/J adult females 13 weeks later. F1 males were mated with BALB/c females and F2 females were than backcrossed to the F1 parents. One BALB/c male mouse thus treated gave origin to a mutant presenting hair and skin alterations similar to those of natural hairless mutants. The new mutation is located on chromosome 14 near the Es10 locus, and probably at the same locus for the hairless mutation. Similar to the hairless mouse, this new mutant has a normal phenotype at birth and after three weeks starts to loose hair which is never replaced. Additionally, the skin becomes thickened and wrinkled. One feature that distinguishes this mutant from other hairless mice is the peculiar enlargement of its axillary and cervical lymph nodes. The new mutant develops membranoproliferative glomerulonephritis similar to the rhino mouse, one of the hairless allele mutants already described in the literature, but with a much later onset.