Yeaman Michael R, Gank Kimberly D, Bayer Arnold S, Brass Eric P
Department of Medicine, Division of Infectious Diseases, Harbor-UCLA Medical Center, Research and Education Institute at Harbor-UCLA, Torrance, California 90502, USA.
Antimicrob Agents Chemother. 2002 Dec;46(12):3883-91. doi: 10.1128/AAC.46.12.3883-3891.2002.
Peptides that exert antimicrobial activity in artificial media may lack activity within blood or other complex biological matrices. To facilitate the evaluation of antimicrobial peptides for possible therapeutic utility, an ex vivo assay was developed to assess the extent and durability of peptide antimicrobial activities in complex fluid biomatrices of whole blood, plasma, and serum compared with those in conventional media. Novel antimicrobial peptides (RP-1 and RP-11) were designed based in part on platelet microbicidal proteins. RP-1, RP-11, or gentamicin was introduced into biomatrices either coincident with, or 2 h prior to, inoculation with an Escherichia coli target organism. Antimicrobial activities of peptides were assessed by quantitative culture 2 h after bacterial inoculation and compared to those of peptide-free and gentamicin controls. In whole blood and homologous plasma or serum, introduction of RP-1 or RP-11 coincident with E. coli was associated with a significant reduction in CFU per milliliter versus the respective peptide-free controls. Moreover, substantial antimicrobial activity remained when RP-1 or RP-11 was placed into whole blood or plasma 2 h prior to E. coli inoculation. These results suggest that the peptides were not rapidly inactivated within these biomatrices. Peptide antimicrobial activities were negatively affected by preincubation in serum or in heat-inactivated serum, compared with those of the respective controls. Peptides RP-1 and RP-11 were consistently effective at lower concentrations in biomatrices than in artificial media, indicating favorable antimicrobial interactions with components of blood or blood fractions. Collectively, these findings support the concept that synthetic peptides can be designed to exert potent antimicrobial activities in relevant and complex biological matrices.
在人工培养基中具有抗菌活性的肽在血液或其他复杂生物基质中可能缺乏活性。为了便于评估抗菌肽的潜在治疗效用，开发了一种体外试验，以评估与传统培养基相比，抗菌肽在全血、血浆和血清等复杂液体生物基质中的抗菌活性程度和持续时间。新型抗菌肽（RP-1和RP-11）部分基于血小板杀菌蛋白进行设计。将RP-1、RP-11或庆大霉素在接种大肠杆菌靶标生物的同时或提前2小时引入生物基质中。在细菌接种2小时后通过定量培养评估肽的抗菌活性，并与无肽对照和庆大霉素对照进行比较。在全血和同源血浆或血清中，与大肠杆菌同时引入RP-1或RP-11与每毫升菌落形成单位相对于各自的无肽对照显著减少有关。此外，在大肠杆菌接种前2小时将RP-1或RP-11置于全血或血浆中时，仍保留大量抗菌活性。这些结果表明，这些肽在这些生物基质中不会迅速失活。与各自的对照相比，肽的抗菌活性在血清或热灭活血清中预孵育后受到负面影响。与在人工培养基中相比，肽RP-1和RP-11在生物基质中在较低浓度下始终有效，表明与血液或血液成分有良好的抗菌相互作用。总的来说，这些发现支持了这样一种观点，即可以设计合成肽在相关和复杂的生物基质中发挥强大的抗菌活性。
