ATHYMIC Nude mouse

The athymic nude mouse is a laboratory mouse originating from a strain presenting a natural genetic mutation causing a total or partial absence of the thymus, a characteristic accompanied by a deficient immune system due to a reduced number of produced T lymphocytes. The three main defects of the homozygous mice for the spontanous mutation “nude” are an abnormal growth of hair, a defective development of the thymic epithelium and a lack of immunity. Even though the mice seem hairless, they are born with follicles for the growth of hair partially defective. The growth cycles and models of the hair are evident, in particular in case of pigmented mice, but the defective follicles don’t allow the hair to grow correctly during the entire cycle. The phenotype of the athymic nude model is characterized by the absence of hair, which gave it the “nude” name. The gene responsible for the mutation has been categorised as being a member of the Fox gene family and the nomenclature recommends the denomination Foxn1nu/nu.

The athymic nude mouse is obtained by fixing the gene Foxn1nu/nu on a genetic BALB/cAnNRj background and by proceeding with the breeding of this new strain in outbreeding mode.

The animal has either no thymus (total absence), or, if it is present, it is generally partial and not functional. The mouse is unable to produce T lymphocytes and is therefore immunodeficient. It suffers from a lack of cell-mediated immunity: the nude homozygous mice presents a partial defect in the development of B cells. Because of a defect in the activity of lymphocytes T helper, the response to thymus-dependent antigens are, when detectable, mostly limited to lgM.

The athymic nude mouse is precious for research, because it can receive different tissue or tumour transplants without rejecting them. These xenografts are often used in research to test new methods of imaging or anti-tumour treatments.

CHARACTERISTICS
The nude homozygous females are not efficient breeders. The ovulation starts late at 2,5 months and ends early at 4 months.
Hairless (no fur), albino background.
Bred in outbreeding mode.

Main application and research fields