Thy-1 determinants are present on many murine hematopoietic cells other than T cells.

The development of a highly amplified immunofluorescence assay and the availability of monoclonal anti-Thy-1 antibodies have provided the methodology to reexamine the presence of Thy-1 antigen on murine lymphohematopoietic cells. The representation of this antigen is not, as previously believed, restricted to the T cell compartment of these cells. It is present on a significant number of mouse bone marrow cells (25-30%), including, as in the rat, multipotential stem cells, prothymocytes and some B cell precursors. Eosinophils and some immature myeloid cells are also antigen-positive.