Lim P L
Department of Microbiology, University of Hong Kong.
J Immunol Methods. 1990 Dec 31;135(1-2):257-61. doi: 10.1016/0022-1759(90)90279-5.
A simple and rapid test (LIMM, short for latex immunoassay) is described for detecting Salmonella typhi endotoxin. It involves the simultaneous binding of the antigen by two types of reagent particles contained in a micro-tube: an indicator latex particle coated with a monoclonal antibody specific for the O-9 determinant on the endotoxin, and a magnetic bead coated with another monoclonal antibody specific for a different O-determinant. At the end of-the test, the magnetic beads are sedimented by use of a magnet, and the result is read based on the turbidity of the indicator latex suspension. Compared to a similar assay developed previously which uses only a single particle reagent (i.e., a tube agglutination system), LIMM was found to be slightly more sensitive especially when using short (less than 30 min) incubation times, and was at all times easier to read. The sensitivity of LIMM, in fact, increased with increasing time of incubation. When compared to the sensitivity (25 ng/ml) of a conventional slide latex agglutination test performed using the same indicator latex reagent, this parameter was 0-, 4.9-, 12.5- and 28.7-fold better after 5, 15, 30 and 60 min of incubation in the LIMM.
本文描述了一种用于检测伤寒沙门氏菌内毒素的简单快速检测方法（LIMM，乳胶免疫测定的简称）。该方法涉及在微量管中两种试剂颗粒同时结合抗原：一种是包被有针对内毒素O-9决定簇的单克隆抗体的指示乳胶颗粒，另一种是包被有针对不同O-决定簇的另一种单克隆抗体的磁珠。在检测结束时，使用磁铁使磁珠沉淀，然后根据指示乳胶悬浮液的浊度读取结果。与先前开发的仅使用单一颗粒试剂的类似检测方法（即试管凝集系统）相比，发现LIMM的灵敏度略高，尤其是在短（少于30分钟）孵育时间的情况下，并且在任何时候都更易于读取结果。实际上，LIMM的灵敏度随着孵育时间的增加而提高。与使用相同指示乳胶试剂进行的传统玻片乳胶凝集试验的灵敏度（25 ng/ml）相比，在LIMM中孵育5、15、30和60分钟后，该参数分别提高了0倍、4.9倍、12.5倍和28.7倍。
