Defective development of the thymus and immunological abnormalities in the neurological mouse mutation "staggerer".

The autosomal recessive mouse mutation "staggerer" (sg/sg), located on chromosome 9, has been recognized as a neurological mutant because of movement abnormalities and defective cerebellar development. We show here that the sg/sg mutation not only affects the development of the cerebellum, but also causes developmental and regulatory changes of the immune system: We observed, on gross inspection, a marked delay in the development of sg/sg thymus, generally enlarged lymph nodes, and undersized spleens. When immunized with SRBC, the sg/sg mouse generated, in normal proportions, helper T-cells in vivo and antibody-forming B-cells in vitro; however, a delay in terminating the response and a deficiency in generating suppressor cells was noted. This suggests the existence of a defect in regulatory feedback mechanisms. The marked delay in the growth of the thymus gland was associated with the prolonged existence of cell-surface carbohydrate patterns characteristic of immature thymocytes. The prolonged expression of embryonal cell-surface phenotypes was observed on the surface of cerebellum and thymus (and, to some extent, spleen) but not in cells from other organs.