Selective response of CD5+ B cell malignancies to activation of the CD72 antigen.
The function of the simultaneous expression of CD5 and its ligand CD72 on B cell malignancies like chronic lymphocytic leukemia and mantle cell lymphoma was assessed. It is unknown if reciprocal interactions between CD72 and CD5 exert an autocrine growth-promoting or -inhibiting effect. CD5+ (n = 13) and CD5- (n = 9) B cell malignancies were cultured with the anti-CD72 mAb WL225. For comparison, five other anti-CD72 mAbs were tested. Only CD5+ B cell malignancies proliferated upon CD72 activation (9 out of 13 cases). A strong suppressive effect of IL-4 on the anti-CD72-induced [3H]thymidine incorporation, partially caused by downmodulation of the CD72 expression, was seen. Stimulation of the CD5 antigen by L cells transfected with human CD72 (LhCD72) and the anti-CD5 mAb 1C12 exerted no (n = 9) or a minor effect (2 out of 8 cases), respectively. Finally, the results of CD72 stimulation were compared with CD40 stimulation, as this "CD40 system" is an effective method for stimulating B cell malignancies. In 4 of the 7 anti-CD72 responsive cases a costimulatory effect was seen.
Planken
E V
EV
Department of Hematology, Leiden University Medical Center, The Netherlands.
Van de Velde
H
H
Falkenburg
J H
JH
Thielemans
K
K
Willemze
R
R
Kluin-Nelemans
J C
JC
D015703:Antigens, CD / Q000276:immunology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology / Q000502:physiology; D018956:CD5 Antigens / Q000032:analysis*; D006801:Humans; D015847:Interleukin-4 / Q000502:physiology; D015448:Leukemia, B-Cell / Q000276:immunology*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology*; D015463:Leukemia, Prolymphocytic / Q000276:immunology*; D008213:Lymphocyte Activation; D008228:Lymphoma, Non-Hodgkin / Q000276:immunology*
D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D019013:CD40 Antigens; D018956:CD5 Antigens; C064228:CD72 protein, human; D015847:Interleukin-4