Sager S, Virella G, Chen W Y, Fudenberg H H
Immunology. 1984 May;52(1):67-78.
Salmonella paratyphi B (S. paratyphi B) has been previously characterized as a human T-independent polyclonal B cell activator. To define further the nature of the bacterial structure responsible for these properties, we studied the effects of autoclaving and enzyme treatment of S. paratyphi B on its stimulatory capacity. We found that both autoclaving and papain treatment decreased the ability of S. paratyphi B to induce B cell activation, while trypsin treatment did not affect this capacity. Neither type of treatment affected the binding of S. paratyphi B to lymphocytes, suggesting that binding and B cell stimulation are mediated by different structures. The observation that B cell stimulation was significantly reduced by papain treatment led us to attempt to purify membrane proteins so that we could investigate whether they shared the stimulating capacity of S. paratyphi B. A water-insoluble, 43-45,000 mol. wt. protein, rich in aspartic acid, glutamine, glycine, alanine and leucine, similar in mol. wt. and physicochemical chemical properties to the porins of other gram negative bacteria, was isolated and designated as outer membrane protein (OMP). This protein was equally efficient to S. paratyphi B in inducing T-independent B cell activation. By performing time-course studies of [3H]-thymidine incorporation we observed a burst of mitogenic activity after stimulation of PBL or purified B cells with both S. paratyphi B and OMP peaking at 48-96 hr of culture (compared to 96-120 hr for the PWM proliferation peak), and with a magnitude of roughly 10% of that observed after PWM stimulation. Given the fact that the proportion of B lymphocytes in PBL is 4-12%, it appears likely that the proliferation burst seen with S. paratyphi B and OMP corresponds to a mitogenic effect mainly restricted to the B cell population.
副伤寒乙沙门氏菌（S. paratyphi B）先前已被鉴定为一种人类非T细胞依赖性多克隆B细胞激活剂。为了进一步确定负责这些特性的细菌结构的性质，我们研究了副伤寒乙沙门氏菌的高压灭菌和酶处理对其刺激能力的影响。我们发现，高压灭菌和木瓜蛋白酶处理均降低了副伤寒乙沙门氏菌诱导B细胞激活的能力，而胰蛋白酶处理则不影响该能力。两种处理方式均未影响副伤寒乙沙门氏菌与淋巴细胞的结合，这表明结合和B细胞刺激是由不同结构介导的。木瓜蛋白酶处理显著降低B细胞刺激的观察结果促使我们尝试纯化膜蛋白，以便我们能够研究它们是否具有副伤寒乙沙门氏菌的刺激能力。分离出一种水不溶性、分子量为43 - 45,000道尔顿的蛋白质，富含天冬氨酸、谷氨酰胺、甘氨酸、丙氨酸和亮氨酸，其分子量和理化性质与其他革兰氏阴性菌的孔蛋白相似，被命名为外膜蛋白（OMP）。这种蛋白质在诱导非T细胞依赖性B细胞激活方面与副伤寒乙沙门氏菌同样有效。通过对[3H] - 胸腺嘧啶核苷掺入进行时间进程研究，我们观察到用副伤寒乙沙门氏菌和OMP刺激外周血淋巴细胞（PBL）或纯化的B细胞后，促有丝分裂活性在培养48 - 96小时达到峰值（相比之下，PWM增殖峰值在96 - 120小时），其幅度约为PWM刺激后观察到的10%。鉴于PBL中B淋巴细胞的比例为4 - 12%，副伤寒乙沙门氏菌和OMP所观察到的增殖爆发似乎主要对应于主要局限于B细胞群体的促有丝分裂效应。
