Isoenzyme studies in human leukemia-lymphoma cell lines--III. beta-Hexosaminidase (E.C. 3.2.1.30)

The hexosaminidase (beta-N-acetylglucosaminidase) isoenzyme profiles of 86 human hematopoietic cell lines grown actively in suspension culture were analysed by isoelectric focusing and by conventional disc electrophoresis on horizontal thin-layer polyacrylamide gels. A maximum of three hexosaminidase (Hex) isoenzymes (A = anodic, I = intermediate, B = basic) could be demonstrated. The immunological phenotyping of 74 leukemia-lymphoma derived cell lines had led to a categorization into four groups with a subclassification of the T- and B-cell lines into several stages of differentiation: 26 T-cell, 34 B-cell, 6 myelomonocytic and 8 Non-T, Non-B cell leukemia-lymphoma cell lines. Twelve so-called 'normal' B-lymphoblastoid cell lines were also available. Distinct isoenzyme profiles were seen in the different stages of differentiation in the T- and B-leukemia-lymphoma cell lines. Among the 12 normal B-lymphoblastoid cell lines heterogeneity in the isoenzymatic phenotypes was detected. Hex isoenzyme expression in normal and neoplastic lymphoid cell lines represents hypothetically sequential stages of T- and B-cell differentiation. Myelomonocytic cell lines displayed strongly stained bands of all three isoenzymes. Heterogeneity was seen in the group of Non-T, Non-B cell lines. Four out of 5 pre B-cell lines and 4 out of 4 Non-T, Non-B cell lines which are comparable to cases of pre B- and common ALL revealed a high Hex I/Hex A ratio in terms of intensity of the isoenzyme bands. The analysis of Hex isoenzymes is useful for characterizing lymphoid and myeloid populations (both normal and malignant, cultured or fresh), particularly with regard to their stage of differentiation. But this enzyme should be part of a multiple enzyme study where the information obtained is complementary. In turn, enzyme marker analysis should be included in the multiple marker analysis for an optimized characterization of leukemic cells.