A CELL surface differentiation antigen known as Thy-1 (formerly called theta1) is expressed during development of brain and thymocytes in both rat and mouse (see ref. 2 for review). Thy-1 is present in brain and on thymocytes throughout adult life, as well as on a subpopulation of peripheral lymphocytes. Both rat and mouse fibroblasts, and some fibroblastic cell lines, express Thy-1 in vitro3 and mouse Thy-1 has been reported on epidermal cells (see ref. 2 for review) and a mammary tumour4. The Thy-1 antigen has been reported lacking in other adult tissues, including muscle1. We present here evidence for an antigen with the serological specificity of Thy-1 on rat myogenic cell lines and embryonic rat muscle differentiating in vitro. The presence of the antigen was transitory, being expressed on myoblasts and newly developed myotubes, but disappearing as myotubes differentiated.
ASJC Scopus subject areas