Ecto-5'-nucleotidase activities in B lymphoblastoid cell lines at various stages of maturation.

Abstract

B lymphoblastoid cell lines (LCL) at various stages of maturation, including possible precursor B cell lines without immunoglobulin (Ig) expression, pre-B cell-like LCL, and Igsecreting LCL, were established from peripheral and bone marrow mononuclear cells of four patients with congenital agammaglobulinemia (CAG) by infection with Epstein-Barr virus (EBV) and estimated for their ecto-5'-nucleotidase (ecto-5'-NT, E.C. 3.1.3.5) activity. Ecto-5'-NT activities in Ig-secreting LCL derived from CAG patients fell into the same range of those in LCL derived from control subjects (from 7.3 to 33.0 nmoles/hr/lO6cells). When ecto-5'-NT activities of precursor B cell lines derived from the CAG patients were also compared with Ig-secreting LCL derived from control subjects, no significant difference in ecto-5'-NT activities was found among LCL with various Ig expression which might indicate various stages of B cell maturation. These results may suggest that ecto-5'-NT does not appear to be a biochemical marker of B cell maturation.ecto-5'-nucleotidase; B cell maturation; congenital agammaglobulinemia; Epstein-Barr virus-induced precursor B cell lines It has been proposed that ecto-5'-NT could be a biochemical marker of B cell maturation, because immature B lymphocytes such as B lymphoblasts of chronic lymphocytec leukemia (CLL) and cord blood B lymphocytes had lower ecto-5'-NT activity than mature B lymphocytes (Quagliata et al. 1974;Boss et al. 1979;Rowe et al. 1980). The low ecto-5'-NT activities were then found in lymphocytes from patients with adult onset hypogammaglobulinemia (Johnson et al. 1977) and congenital agammaglobulinemia (CAG) (Edwards et al. 1978;Webster et al. 1978). In view of these findings, Thompson et al. (1980) suggested that the decreased activity in lymphocytes of CAG patients was the result of a lack of ecto-5'-NT activity in B cells which were prevented from maturing at an early stage before the acquisition of surface immunoglobulin (sIg).However, ecto-5'-NT activities of B lymphoblastoid cell lines (LCL), which were established by infectionn with Epstein-Barr virus (EBV) of peripheral blood mononuclear cells (PBM) from CAG patients were not different in range from those of LCL derived from PBM of healthy controls ).