Evidence that murine Vγ5 and Vγ6 γδ-TCR⁺ lymphocytes are derived from a common distinct lineage

Murine Vγ5 and Vγ6⁺ T lymphocytes develop sequentially in the thymus during fetal and newborn life, giving rise to intraepithelial lymphocytes of the epidermis and female reproductive tract. In analyzing a panel of γδ T cell hybridomas derived from various tissues, we found that all Vγ6⁺ cells tested (n = 25) expressed Vγ5-Cγ1 mRNA, whereas none of a panel of Vγ6^- cells analyzed (n = 33) expressed this mRNA. Vγ6 mRNA was rare in Vγ5⁺ cells (1 of 9), and absent in all other γδ T cells (n = 10). These findings suggest that most, if not all, Vγ6-TCR⁺ lymphocytes arise from precursor cells that have previously rearranged the Vγ5 gene, and indicate that Vγ5 and Vγ6⁺ lymphocytes belong to a common, distinct lineage that does not give rise to other γδ T cells.