Smith G, Morrison C A, Maddison P J
ARC Research Group, Royal National Hospital for Rheumatic Diseases, Bath, UK.
Clin Exp Immunol. 1987 Jun;68(3):552-61.
The effect of affinity purified La(SSB) on immunoglobulin synthesis in vitro by mononuclear cells (MNC) from anti-La(SSB)-positive systemic lupus erythematosus (SLE) patients and healthy controls was studied. La(SSB) was prepared from calf thymus extract and characterized by SDS-polyacrylamide gel electrophoresis and immunoblotting. Silver staining of gels reveals nine major bands at 68 kD, 43-48 kD and 30-33 kD, of which six were recognized on immunoblots by sera from anti-La(SSB) positive SLE patients. Studies in vitro showed that La(SSB) alone did not stimulate total IgG or IgM synthesis in controls or SLE patients. Low concentrations of La(SSB) (optimal dose less than 0.02 ng/ml) suppressed pokeweed mitogen (PWM)-driven IgG synthesis by controls but not by anti-La(SSB) positive SLE patients. IgM responses were unaffected. Anti-La(SSB) and anti-DNA were detected in PWM-stimulated cultures from both study groups. In the presence of La(SSB) IgM anti-La(SSB) synthesis was enhanced in anti-La(SSB)-positive patients in a dose-dependent manner. In contrast, La(SSB) inhibited anti-La(SSB) production by controls (maximal at 2 ng/ml). La(SSB) had no effect on anti-DNA production in either group. Pre-incubation of control or anti-La(SSB)-positive SLE MNC with La(SSB) before addition to autologous PWM-driven cultures did not induce suppressor cells, although pre-incubation with Concanavalin A (ConA) did. Thus we suggest that La(SSB)-induced suppression of IgG synthesis in PWM-driven control cultures may not be due to induction of regulator cells, possibly missing from SLE cultures, but perhaps is a direct effect on B cells.
研究了亲和纯化的La(SSB)对来自抗La(SSB)阳性系统性红斑狼疮(SLE)患者和健康对照者的单核细胞(MNC)体外免疫球蛋白合成的影响。La(SSB)从小牛胸腺提取物中制备，并通过SDS-聚丙烯酰胺凝胶电泳和免疫印迹进行鉴定。凝胶的银染色显示在68 kD、43 - 48 kD和30 - 33 kD处有九条主要条带，其中六条在免疫印迹上被抗La(SSB)阳性SLE患者的血清识别。体外研究表明，单独的La(SSB)不会刺激对照者或SLE患者的总IgG或IgM合成。低浓度的La(SSB)(最佳剂量小于0.02 ng/ml)抑制对照者由商陆丝裂原(PWM)驱动的IgG合成，但不抑制抗La(SSB)阳性SLE患者的IgG合成。IgM反应不受影响。在两个研究组的PWM刺激培养物中均检测到抗La(SSB)和抗DNA。在La(SSB)存在的情况下，抗La(SSB)阳性患者中IgM抗La(SSB)的合成呈剂量依赖性增强。相比之下，La(SSB)抑制对照者抗La(SSB)的产生(在2 ng/ml时最大)。La(SSB)对两组中的抗DNA产生均无影响。在将对照者或抗La(SSB)阳性SLE的MNC加入自体PWM驱动培养物之前，先用La(SSB)预孵育不会诱导抑制细胞，而用刀豆球蛋白A(ConA)预孵育则会诱导抑制细胞。因此，我们认为La(SSB)在PWM驱动的对照培养物中诱导的IgG合成抑制可能不是由于调节细胞的诱导，SLE培养物中可能缺少调节细胞，但这可能是对B细胞的直接作用。
