Ellis Richard W, Sobanski Michael A
Department of Medical Microbiology, City Hospital NHS Trust, Birmingham B18 7QH and *School of Biosciences, Cardiff University, PO Box 915, Cardiff CF1 3TL.
J Med Microbiol. 2000 Oct;49(10):853-859. doi: 10.1099/0022-1317-49-10-853.
Microbial antigen in clinical specimens can be detected rapidly by commercial test-card latex agglutination, but poor sensitivity is a potential difficulty. Antigen detection by immuno-agglutination of coated latex micro-particles can be enhanced in comparison with the conventional test-card method in both rate and sensitivity by the application of a non-cavitating ultrasonic standing wave. Antibody-coated micro-particles suspended in the acoustic field are subjected to physical forces that promote the formation of agglutinates by increasing particle-particle contact. This report reviews the application of ultrasound to immuno-agglutination testing with several commercial antibody-coated diagnostic micro-particles. This technique is more sensitive than commercial card-based agglutination tests by a factor of up to 500 for fungal cell-wall antigen, 64 for bacterial polysaccharide and 16 for viral antigen (in buffer). The detection sensitivity of meningococcal capsular polysaccharide in patient serum or CSF has been increased to a stage where serotyping by ultrasound-enhanced agglutination is comparable to that achievable with the PCR, but is available more rapidly. Serum antigen concentration as measured by ultrasonic agglutination has prognostic value. Increasing the sensitivity of antigen detection by increasing the acoustic forces that act on suspended particles is considered. Employing turbidimetry to measure agglutination as part of an integrated ultrasonic system would enable the turnover of large numbers of specimens. Ultrasound-enhanced latex agglutination offers a rapid, economical alternative to molecular diagnostic methods and may be useful in situations where microbiological and molecular methods are impracticable.
临床标本中的微生物抗原可通过商用检测卡乳胶凝集法快速检测，但灵敏度欠佳是一个潜在难题。与传统检测卡方法相比，应用非空化超声驻波可提高包被乳胶微粒免疫凝集法检测抗原的速度和灵敏度。悬浮于声场中的抗体包被微粒会受到物理力作用，通过增加颗粒间接触促进凝集物形成。本报告综述了超声在几种商用抗体包被诊断微粒免疫凝集检测中的应用。该技术对于真菌细胞壁抗原的灵敏度比商用卡片凝集试验高500倍，对于细菌多糖高64倍，对于病毒抗原（在缓冲液中）高16倍。超声增强凝集法检测患者血清或脑脊液中脑膜炎球菌荚膜多糖的灵敏度已提高到与PCR相当的水平，但速度更快。通过超声凝集法测定的血清抗原浓度具有预后价值。考虑通过增加作用于悬浮颗粒的声学力来提高抗原检测的灵敏度。采用比浊法测量凝集作为集成超声系统的一部分，可实现大量标本的快速检测。超声增强乳胶凝集法为分子诊断方法提供了一种快速、经济的替代方法，在微生物学和分子方法不可行的情况下可能有用。
