Methylation patterns of the T cell receptor beta-chain gene in T cells, large granular lymphocytes, B cells, and...

We evaluated the methylation state of the T cell receptor beta-chain gene (T beta) DNA of T cells, large granular lymphocytes (LGL), B cells, and monocytes to determine whether methylation can be correlated with the reported transcriptional activity of this gene and whether this methylation pattern can be used as a marker for different leukocyte populations. By using the restriction enzyme isoschizomers, MspI and HpaII, we found that T beta of T cells was highly unmethylated, the gene in B cells and monocytes is highly methylated, and the methylation state of T beta of LGL is intermediate between that of T cells and B cells or monocytes. These results indicate that the methylation pattern of T beta can be a marker for T cells and LGL. The difference in methylation pattern of T beta between LGL and T cells indicated that most LGL were different from T cell populations. The methylation pattern of T beta in LGL DNA was also heterogeneous, in contrast to that of other leukocytes, suggesting that human peripheral blood LGL include several cell subsets. Only T cells, which synthesize full length 1.3-kb transcripts of T beta, have almost completely unmethylated CCGG sequences, indicating a good correlation between the reported level of 1.3-kb mRNA transcription from T beta and hypomethylation of this gene.