Molecular investigation of the cytokines produced by normal and malignant B lymphocytes.
Different normal and malignant human B-cell populations were studied with a twofold aim: to define which cytokines are produced in vivo, and to assess the relationship between cytokine production and kinetic state. To analyse normal B-cells representative of different stages of activation and proliferation in vivo, we purified germinal centre (GC)-B blasts and mantle B (M-B) cells from tonsils. To compare malignant B lymphocytes with their closest normal equivalent cells, we separated malignant CD5+B lymphocytes from the peripheral blood of patients with B-chronic lymphocytic leukemia (B-CLL) and normal CD5+B lymphocytes from cord blood. The expression of interleukins (IL) IL-1 alpha, IL-1 beta, tumour necrosis factor alpha (TNF-alpha), transforming growth factor beta (TGF-beta), IL-2, IL-4, and IL-6 genes was analysed using Northern and Western blotting techniques. TNF-alpha mRNA is produced by resting (M-B) and actively proliferating (GC-B) normal B lymphocytes. TGF-beta mRNA is present at high levels in resting normal M-B cells, while the transcript levels are lower in proliferating GC-B and in activated CD5+B lymphocytes. IL-2 production is limited to the actively proliferating GC-B blasts, IL-1 beta and IL-6 to resting M-B cells. The cytokine production profile of CD5+ malignant B-CLL cells differs from that of their putative normal counterparts and is more like the profile of M-B cells, since B-CLL cells produce IL-1 beta, TNF-alpha, TGF-beta, and IL-6. These observations lead to the following conclusions: among normal B lymphocyte populations, resting M-B lymphocytes are the most active cytokine producers, and B-CLL malignant B cells reflect the production pattern of normal resting B lymphocytes.
Dipartimento di Scienze Biomediche e Oncologia Umana, Sezione Clinica, Torino, Italy.
M
M
Schena
G
G
Gaidano
D
D
Gottardi
F
F
Malavasi
L G
LG
Larsson
K
K
Nilsson
F
F
Caligaris-Cappio
D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D015152:Blotting, Northern; D015153:Blotting, Western; D018956:CD5 Antigens; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics; D007376:Interleukin-2 / Q000235:genetics; D015847:Interleukin-4 / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D015448:Leukemia, B-Cell / Q000097:blood / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008213:Lymphocyte Activation; D014066:Palatine Tonsil / Q000166:cytology; D011506:Proteins / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D015703:Antigens, CD; D018956:CD5 Antigens; D016207:Cytokines; D007375:Interleukin-1; D007376:Interleukin-2; D015850:Interleukin-6; D011506:Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4