Functional role of CD26 on human B lymphocytes.
CD26 is a well-known activation marker on T cells and natural killer (NK) cells [1]. It is identical with the ectopeptidase dipeptidyl peptidase IV (DP IV). The expression of CD26 on B cells has been discussed controversially [2,3]. We have studied the expression of this enzyme on B cells from the peripheral blood of healthy donors and of CVID patients, on cells of the Daudi Burkitt line and the EBV-transformed B-cell lines Jojo and Laz509. DP IV was detected by using anti-CD26 monoclonal antibodies and with help of specific enzyme substrates. Further the influence of specific synthetic DP IV inhibitors on mitogenic activation of purified B cells and DNA synthesis of cell lines was studied. We could show that in both groups 0-5% of freshly isolated CD20-positive B cells do express the CD26 antigen. After stimulation with pokeweed mitogen or St. aureus protein, the fraction of CD26-positive cells was enhanced up to 51% and 36%, respectively. Interestingly, induction of CD26 expression on B cells from CVID patients occurs in a manner similar to the B cells from healthy donors. Treatment of peripheral blood B cells and B-cell lines with highly specific competitive DP IV inhibitors leads to a significant inhibition of DNA synthesis in a dose-dependent manner. These data show that CD26 can be considered to be an activation marker not only of T- and NK cells but also of a main population of B cells, suggesting an involvement of CD26 in B-cell activation.
Bühling
F
F
Institute of Experimental Internal Medicine, Otto von Guericke University Magdeburg, Germany.
Junker
U
U
Reinhold
D
D
Neubert
K
K
Jäger
L
L
Ansorge
S
S
D001402:B-Lymphocytes / Q000201:enzymology / Q000276:immunology*; D002051:Burkitt Lymphoma / Q000473:pathology; D002461:Cell Line, Transformed; D004261:DNA Replication / Q000187:drug effects; D018819:Dipeptidyl Peptidase 4 / Q000502:physiology*; D006801:Humans; D007075:Immunoglobulin M / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000187:drug effects; D011043:Pokeweed Mitogens / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000276:immunology; D014407:Tumor Cells, Cultured
D007075:Immunoglobulin M; D011043:Pokeweed Mitogens; D018819:Dipeptidyl Peptidase 4