BALB/c nude Mice

● The autosomal recessive nude gene in homozygous (sp/sp) mice causes the absence of fur and an abnormal thymus. The deficiency in T cell function allows athymic mice to accept and grow xenografts as well as allografts of normal and malignant tissues.

● Heterozygous (sp/wt) mice have hair. Heterozygous mutant nudes were originally thought to have normal immune systems, but in fact have immune alterations such as reduced bone marrow stem cells and lower thymus weights. Heterozygous nudes may thus not be appropriate for use as sentinels, but may be used in PK/dosing studies.

In general, nude mice make ideal hosts for established, rapidly growing tumor cell lines. Its hairless phenotype eases the evaluation of subcutaneous tumor growth. However, because nude mice still have B cells and robust natural killer (NK) cell responses, they are not suitable hosts for blood-borne cancers, such as leukemias or lymphomas.