Inhibitory effect of anti-class II antibody on the spontaneous activation of B cells in patients with systemic lupus erythematosus. Analysis with IL-1 production and IL-1 receptor expression.
The mechanism of the spontaneous activation of B cells in patients with SLE was analyzed from the standpoint of the production of IL-1 from B cells and the expression of IL-1R on B cells. SLE B cells spontaneously produced IL-1-like factors which stimulated murine thymocyte proliferative responses. Their m.w. was about 17,000 and their isoelectric point was 4.8. The IL-1-like activity produced by B cells was absorbed with rabbit anti-IL-1 alpha antibody, but not with anti-IL-1 beta antibody. The differentiation of SLE B cells was enhanced by rIL-1 alpha, beta or IL-1-like factors produced by SLE B cells in a concentration-dependent manner. SLE B cells expressed large number of IL-1R detected by FITC-conjugated IL-1 alpha. By a Percoll gradient density centrifugation, IL-1-producing cells and B cells responsive to IL-1 were enriched in a higher density fraction, but were reduced in a lower density fraction. IL-1R-positive B cells were enriched in the lower density fraction, but were depleted in the higher density fraction. However, the expression of IL-1R on the lower density B cells was reduced by 2-day culture. The expression of IL-1R on the higher density B cells was increased during a 2-day culture. Anti-class II antibody inhibited the production of IL-1R on the higher density B cells. These results suggest that the cellular interaction among B precursor cells mediated by class II Ag induces the production of IL-1 and the expression of its receptors on their surface and the interaction between IL-1 and its receptors stimulates B precursor cells to spontaneously differentiate into Ig-producing cells as an autocrine mechanism in patients with SLE.
Tanaka
Y
Y
First Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Saito
K
K
Suzuki
H
H
Eto
S
S
Yamashita
U
U
D000961:Antilymphocyte Serum / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D001667:Binding, Competitive; D002454:Cell Differentiation / Q000187:drug effects; D006681:HLA-D Antigens / Q000276:immunology*; D006801:Humans; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000494:pharmacology; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation; D011971:Receptors, Immunologic / Q000032:analysis*; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins / Q000494:pharmacology
D000961:Antilymphocyte Serum; D006681:HLA-D Antigens; D007375:Interleukin-1; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins