Synthesis of immunoglobulin G by pokeweed mitogen- or Epstein-Barr virus-stimulated human B cells in vitro is restricted to the ecto-5'-nucleotidase positive subset.
Ecto-5'-nucleotidase (ecto-5'-NT) is believed to be a maturation marker for human B lymphocytes because its expression increases during normal development and is reduced in many patients with B cell immunodeficiencies. To determine whether this enzyme defines functional subsets of B lymphocytes, human peripheral blood B cells, separated into ecto-5'-NT positive and negative populations by using goat anti-5'-NT antibodies and the fluorescence-activated cell sorter, were compared for their ability to secrete polyclonal immunoglobulin. Both populations synthesized equivalent quantities of IgM in response to a T cell-dependent (PWM) or T cell-independent (EBV) stimulator of polyclonal immunoglobulin biosynthesis. However, ecto-5'-NT+ B lymphocytes synthesized 8- to 26-fold more IgG per cell than ecto-5'-NT- B cells. These data provide the first direct evidence that ecto-5'-NT is a marker for the functional maturation of human B cells and support the hypothesis that ecto-5'-NT deficiency in patients with hypogammaglobulinemia results from a block in B lymphocyte maturation.
Thompson
L F
LF
Department of Immunology, Scripps Clinic, La Jolla, California 92037.
Ruedi
J M
JM
D015720:5'-Nucleotidase; D000328:Adult; D001402:B-Lymphocytes / Q000145:classification / Q000201:enzymology* / Q000378:metabolism; D002469:Cell Separation; D002472:Cell Transformation, Viral; D004854:Herpesvirus 4, Human; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007075:Immunoglobulin M / Q000096:biosynthesis; D008213:Lymphocyte Activation; D009708:Nucleotidases / Q000378:metabolism*; D010641:Phenotype; D011043:Pokeweed Mitogens
D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011043:Pokeweed Mitogens; D009708:Nucleotidases; D015720:5'-Nucleotidase