The thiol-proteindisulfide oxidoreductase in human mononuclear cells of blood and bone marrow.
The in vivo function of the thiol-proteindisulfide oxidoreductase (TPO, EC 1.8.4.2; proteindisulfide isomerase, EC 5.3.4.1) in biosynthesis of immunoglobulin was investigated by studying the enzyme content in human lymphoid and other cells by an immunocytochemical method. In contrast to peripheral blood, B lymphocytes which showed no or no demonstrable TPO, normal as well as malignant bone marrow plasma cells (all Ig classes) were found to contain abundant amounts of this enzyme. TPO containing plasma cells were identified by double-staining techniques. This finding suggests that TPO is involved in the terminal step of B cell differentiation and immunoglobulin biosynthesis. Besides plasma cells, approximately 10% of mononuclear marrow cells as yet unidentified medium-sized and large cells, exhibited also strong anti-TPO reactivity. Furthermore, using surface-cytoplasmic double staining methods, monocytes from human peripheral blood could be identified to represent the only cytoplasmic TPO-containing normal mononuclear blood cells.
S
S
Ansorge
H W
HW
Mansfeld
C
C
Held
L
L
Broodtaerts
B
B
van Camp
D001402:B-Lymphocytes / Q000201:enzymology; D001853:Bone Marrow / Q000201:enzymology*; D001854:Bone Marrow Cells; D005455:Fluorescent Antibody Technique; D006801:Humans; D007535:Isomerases / Q000032:analysis / Q000097:blood*; D007962:Leukocytes / Q000145:classification / Q000201:enzymology*; D009000:Monocytes / Q000201:enzymology; D010950:Plasma Cells / Q000201:enzymology; D019704:Protein Disulfide-Isomerases; D013194:Staining and Labeling
D007535:Isomerases; D019704:Protein Disulfide-Isomerases