Activated human monocytes inhibit the intracellular multiplication of legionnaires’ disease bacteria

We have examined the interaction between virulent egg yolk-grown L. pneumophila, Philadelphia 1 strain, and in vitro-activated human monocytes, under antibiotic-free conditions. Freshly explanted human monocytes activated by incubation with concanavalin A (Con A) and human lymphocytes inhibited the intracellular multiplication of L. pneumophila. Both Con A and lymphocytes were required for activation. Con A was consistently maximally effective at greater than or equal to 4 μg/ml. Monocytes activated by incubation with cell-free filtered supernatant from Con A-sensitized mononuclear cell cultures also inhibited the intracellular multiplication of L. pneumophil a. The most potent supernatant was obtained from mononuclear cell cultures incubated with greater than or equal to 15 μg/ml Con A for 48 h. The degree of monocyte inhibition of L. pneumophila multiplication was proportional to the length of time monocytes were preincubated with supernatant (48 {greater than} 24 {greater than} 12 h) and to the concentration of supernatant added (40 percent {greater than} 20 percent {greater than} 10 percent {greater than} 5 percent). Monocytes treated with supernatant daily were more inhibitory than monocytes treated initially only. With time in culture, monocytes progressively lost a limited degree of spontaneous inhibitory capacity and also lost their capacity to respond to supernatant with inhibition of L. pneumophila multiplication. Supernatant-activated monocytes inhibited L. pneumophila multiplication in two ways. They phagocytosed fewer bacteria, and they slowed the rate of intracellular multiplication of bacteria that were internalized. As was the case with nonactivated monocytes, antibody had no effect on the rate of intracellular multiplication in supernatant-activated monocytes. Neither supernatant-activated nor nonactivated monocytes killed L. pneumophila in the absence of antibody. Both killed a limited proportion of these bacteria in the presence of antibody and complement. We have previously reported that anti-L, pneumophila antibody and complement neither promote effective killing of L. pneumophila by human polymorphonuclear leukocytes and monocytes nor inhibit the rate of L. pneumophila multiplication in monocytes. These findings and our present report that activated monocytes do inhibit L. pneumophila multiplication indicate that cell-mediated immunity plays a major role in host defense against Legionnaires’ disease.     

人表皮细胞与角膜上皮细胞蛋白质组的差异表达初步研究

目的：应用蛋白质组技术比较人表皮细胞与角膜上皮细胞之间的蛋白质表达差异。方法：实验于2005-11，2006-10在中山大学中山眼科中心国家眼科学重点实验室完成。分别培养人表皮细胞与角膜上皮细胞，裂解原代细胞抽提总蛋白，精确定量后进行双向电泳，扫描电泳凝胶获得二维总蛋白图谱。图谱使用软件辅助比较分析，找出差异表达点，从凝胶中抠取差异点，胶内酶解后用基质辅助激光解吸附，电离飞行时间串级质谱法鉴定差异蛋白。结果：人表皮细胞与角膜上皮细胞蛋白质凝胶分析获得600余个清晰的蛋白质斑点，在比较分析出的26个差异点中初步鉴定出4个差异表达蛋白，分别是细胞内氯离子通道1、Psodasin、乳酸脱氢酶B和丝氨酸蛋白酶抑制因子。结论：人表皮细胞与角膜上皮细胞在蛋白质表达上有较高的相似性以及较好的可比性，为探索表皮细胞横向分化成角膜上皮细胞的分子机制做出了有益的尝试，并提供了具有一定可操作性的实验方法。     

DIGITAL ISCHAEMIA: AN UNUSUAL PRESENTATION OF DYSBARISM

SUMMARY Dysbaric symptoms following ascent from a scuba dive are due to symptomatic nitrogen or air emboli with clear patterns of associated injury. This case report highlights an unusual presentation of dysbaric injury treated successfully with a prostacyclin analogue.