Johannsen L, Wecke J, Obál F, Krueger J M
Department of Physiology and Biophysics, University of Tennessee, Memphis 38163.
Am J Physiol. 1991 Jan;260(1 Pt 2):R126-33. doi: 10.1152/ajpregu.1991.260.1.R126.
Muramyl peptides have a variety of biological effects in mammals, including enhancement of the immune response, sleep, and body temperature. Although mammals lack biosynthetic pathways for muramyl peptides, they are found in mammals and are well known as components of bacterial cell walls. This suggests that phagocytic mammalian cells digest bacterial cell walls and produce biologically active muramyl peptides. Staphylococcal cell walls were radioactively labeled during growth of the bacteria. During the digestion of these radiolabeled bacteria, murine bone marrow macrophages produced low-molecular-weight substances that coeluted chromatographically with the radioactive cell wall marker. Further separation of these substances using reversed-phase high-performance liquid chromatography resulted in the isolation of substances with high specific biological activity. Intracerebroventricular injection of rabbits with these substances induced an increase in slow-wave sleep and body temperature and a suppression of rapid-eye-movement sleep. The characteristics of the biological responses and the chromatographic behavior of the active components are consistent with those of muramyl peptides. The ability of macrophages to tailor muramyl peptides from peptidoglycan may provide an amplification step for the immune response. Muramyl peptides released by macrophages may also act as mediators for various facets of the acute phase response elicited by bacterial infections such as fever and sleep.
胞壁酰肽在哺乳动物中具有多种生物学效应，包括增强免疫反应、影响睡眠和体温。尽管哺乳动物缺乏胞壁酰肽的生物合成途径，但它们在哺乳动物体内被发现，并且作为细菌细胞壁的成分而广为人知。这表明吞噬性哺乳动物细胞会消化细菌细胞壁并产生具有生物活性的胞壁酰肽。在细菌生长期间，葡萄球菌细胞壁被放射性标记。在消化这些放射性标记的细菌过程中，小鼠骨髓巨噬细胞产生了低分子量物质，这些物质在色谱上与放射性细胞壁标记物共洗脱。使用反相高效液相色谱对这些物质进行进一步分离，得到了具有高比生物活性的物质。给兔子脑室内注射这些物质会导致慢波睡眠增加、体温升高以及快速眼动睡眠受到抑制。生物反应的特征以及活性成分的色谱行为与胞壁酰肽一致。巨噬细胞从肽聚糖中定制胞壁酰肽的能力可能为免疫反应提供一个放大步骤。巨噬细胞释放的胞壁酰肽也可能作为细菌感染引发的急性期反应各个方面（如发热和睡眠）的介质。
