Subpopulations of CD4−, CD8− thymocytes

Abstract
A population of highly purified CD4, CD8 thymocytes was analyzed by both flow microfluorometry and in situ hybridization in an attempt to further elucidate thymocyte subpopulations. The double-negative cells had a marked increase in expression of the c-myb and T cell gamma genes relative to unseparated thymocytes. Approximately 27% were Ly-24+, 8% Ly-6C+ and 6% 6B2+. All of the Ly-6C+ cells were also Ly-24+. A small population (6%) of the CD4, CD8 thymocytes had surface expression of the T cell receptor for antigen (F23.1); all were bright Ly-1+ and half were Ly-24+. These studies demonstrate that there are further subdivisions of the CD4, CD8 thymocytes based upon cell surface expression of markers previously found on bone marrow cells and their non-T cell progeny. Studies are in progress to determine whether these represent different stages of activation-maturation or different lineages of cells.