Molecular Structure of the Rearranged T-Cell Gamma Chain Gene in a Human Leukemia Which Expresses Its Product

The gamma gene product is a component of the second T-cell receptor. We report a new case of acute lymphoblastic leukemia bearing a CD3+ CD4- CD5+ CD7+ CD8- WT31- immunophenpotype that expresses the gamma peptide. Immunoprecipitation studies using an anti Cγ heteroantisera showed two different bands of 40 and 60 Kd. Southern analysis revealed Cγ1 utilization in the productive rearrangement. The demonstration of Vδ-Jδ1 rearrangement in this leukemia suggests that the 60 Kd band could correspond to the product of the delta gene. The utilization of the Jγ1.3 exon in this leukemia suggests that the T lymphocytes that undergo leukemic transformation are derived from a population different from the circulating γ/δ lymphocytes, that preferentially use the Jγ1.2 (JγP) exon.