The influence of follicular dendritic cells on B-cell proliferation depends on the activation of B cells and the mitogen used.
Follicular dendritic cells (FDC) are unique non-lymphoid cells found only in lymph follicles. They play a part in the survival, proliferation and differentiation of B cells. To analyse the influence of FDC on B-lymphocyte proliferation, we isolated them from human tonsils on albumin gradients and treated them with mitomycin C to prevent the multiplication of lymphoid cells harboured in their cytoplasmic evaginations. FDC cultured for 12-16 h remained attached to the substrate; non-adherent cells were carefully eliminated by washing. Purified B cells cultured alone or with contaminant-cleared FDC were maintained for 2 days in the presence or absence of various stimulants, after which tritiated thymidine uptake by these cells was measured. In the absence of activators, FDC did not induce B-cell multiplication. B cells cultured in the presence of FDC exhibited increased 3H-TdR uptake when activated with anti-CD40 MoAb, anti-immunoglobulin MoAb or transferrin, but not when stimulated with Staphylococcus aureus strain Cowan I (SAC) at a given concentration. In the latter case, B-cell proliferation clearly decreased. In control cocultures where mitomycin-C-treated non-adherent cells were used instead of FDC in the presence of the different stimulants, no increase in B-cell proliferation was observed. The results suggest that, inside the germinal centres, FDC modulation of B-cell proliferation depends on the activation state of the B cells and on the stimulant encountered.
Bosseloir
A
A
Institute of Human Histology, University of Liège, Belgium.
Bouzahzah
F
F
Defrance
T H
TH
Heinen
E
E
Simar
L J
LJ
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001402:B-Lymphocytes / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology; D002455:Cell Division; D002469:Cell Separation; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004261:DNA Replication; D003713:Dendritic Cells / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D008934:Mitogens / Q000494:pharmacology*; D016685:Mitomycin / Q000494:pharmacology; D014066:Palatine Tonsil / Q000166:cytology; D013211:Staphylococcus aureus / Q000276:immunology; D014168:Transferrin / Q000276:immunology
D000903:Antibiotics, Antineoplastic; D000911:Antibodies, Monoclonal; D019013:CD40 Antigens; D007074:Immunoglobulin G; D008934:Mitogens; D014168:Transferrin; D016685:Mitomycin