Mouse bone marrow-derived mast cells and mast cell lines constitutively produce B cell growth and differentiation activities.
The present report describes a novel function of mast cells that consists of a B cell growth activity. The B cell response occurred without any stimulation or preactivation of mast cells. A small number of mast cells was required, since mast cell/B cell ratios as low as 1/100 to 1/10,000 lead to effective B cell activation. Mast cell-dependent B cell activation resulted, within 48 h of incubation, in blast formation, proliferation, and IgM production. Both low and high density B cells were responsive to mast cells. Supernatants from unstimulated mast cells could also activate B cells, suggesting that a B cell-stimulating activity (MC-BSA) is mediated by a soluble factor(s). The addition of anti-IL-4 or anti-IL-6 mAbs or even proteases to the mast cell-derived supernatants did not alter B cell activation. However, treatment of mast cells with mitomycin C or actinomycin D, or paraformaldehyde fixation totally abrogated MC-BSA. Fractionation of mast cell supernatant by gel filtration chromatography resulted in four peaks, ranging from > 200 to 15 kDa, all of which were biologically active on B cells. Because mast cells are known to continuously release proteoglycans, MC-BSA was subjected to chondroitinase and heparinase treatment, but no significant inhibition of B cell activation was obtained. This direct T cell-independent stimulatory effect of mast cells on B cells could account for a mechanism by which plasma cells are continuously produced in lymphoid organs and particularly in bone marrow.
Tkaczyk
C
C
Immunoallergy Unit, Pasteur Institute, Paris, France.
Frandji
P
P
Botros
H G
HG
Poncet
P
P
Lapeyre
J
J
Peronet
R
R
David
B
B
Mécheri
S
S
D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D001685:Biological Factors / Q000096:biosynthesis / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D003609:Dactinomycin / Q000494:pharmacology; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D015847:Interleukin-4 / Q000037:antagonists & inhibitors; D008213:Lymphocyte Activation / Q000187:drug effects*; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008811:Mice, Inbred DBA; D016685:Mitomycin / Q000494:pharmacology; D000093242:Interleukin-6 Inhibitors
D001685:Biological Factors; D003609:Dactinomycin; D000949:Histocompatibility Antigens Class II; D007075:Immunoglobulin M; D015847:Interleukin-4; D016685:Mitomycin; D000093242:Interleukin-6 Inhibitors