Expression of dipeptidylaminopeptidase-IV in some human T and B cell lines

The specificity of the expression of dipeptidylaminopeptidase-IV (DAP-IV) was examined in cells from leukemia patients and in 33 normal and leukemic human cell lines widely used in various studies. There was no correlation between DAP-IV activity and OKT4 positivity or maturation stage in T cells. In addition, DAP-IV was unexpectedly expressed by 4 B cell lines and 1 histiocytic lymphoma cell line, indicating either lack of specificity of DAP-IV or infidelity of gene expression under unnatural culture environment.