On flow cytometric analysis of a sample of fetal thymus, a certain population of cells is identified that is positive for both CD4 and CD8 cell surface antigens. These cells are best characterized as which of the following cells?

Question

On flow cytometric analysis of a sample of fetal thymus, a certain population of cells is identified that is positive for both CD4 and CD8 cell surface antigens.  These cells are best characterized as which of the following cells?

Quizplus · Accepted Answer

Eductional Objective: Immature T-lymphocytes express both the CD4 and CD8 cell surface antigens in addition to a complete TCR or a pro-TCR.  These lymphocytes exist in the thymic cortex where they undergo positive selection and in the thymic medulla where they undergo negative selection.

On Flow Cytometric Analysis of a Sample of Fetal Thymus