Cao L, Chan K M, Chen D, Vanittanakom N, Lee C, Chan C M, Sirisanthana T, Tsang D N, Yuen K Y
Department of Microbiology, The University of Hong Kong.
J Clin Microbiol. 1999 Apr;37(4):981-6. doi: 10.1128/JCM.37.4.981-986.1999.
Mannoproteins are important and abundant structural components of fungal cell walls. The MP1 gene encodes a cell wall mannoprotein of the pathogenic fungus Penicillium marneffei. In the present study, we show that Mp1p is secreted into the cell culture supernatant at a level that can be detected by Western blotting. A sensitive enzyme-linked immunosorbent assay (ELISA) developed with antibodies against Mp1p was capable of detecting this protein from the cell culture supernatant of P. marneffei at 10(4) cells/ml. The anti-Mp1p antibody is specific since it fails to react with any protein-form lysates of Candida albicans, Histoplasma capsulatum, or Cryptococcus neoformans by Western blotting. In addition, this Mp1p antigen-based ELISA is also specific for P. marneffei since the cell culture supernatants of the other three fungi gave negative results. Finally, a clinical evaluation of sera from penicilliosis patients indicates that 17 of 26 (65%) patients are Mp1p antigen test positive. Furthermore, a Mp1p antibody test was performed with these serum specimens. The combined antibody and antigen tests for P. marneffei carry a sensitive of 88% (23 of 26), with a positive predictive value of 100% and a negative predictive value of 96%. The specificities of the tests are high since none of the 85 control sera was positive by either test.
甘露糖蛋白是真菌细胞壁重要且丰富的结构成分。MP1基因编码致病真菌马尔尼菲青霉的一种细胞壁甘露糖蛋白。在本研究中，我们发现Mp1p分泌到细胞培养上清液中的水平可通过蛋白质印迹法检测到。用抗Mp1p抗体开发的一种灵敏的酶联免疫吸附测定（ELISA）能够从每毫升含10⁴个细胞的马尔尼菲青霉细胞培养上清液中检测到这种蛋白。抗Mp1p抗体具有特异性，因为通过蛋白质印迹法它不与白色念珠菌、荚膜组织胞浆菌或新型隐球菌的任何蛋白质形式的裂解物发生反应。此外，这种基于Mp1p抗原的ELISA对马尔尼菲青霉也具有特异性，因为其他三种真菌的细胞培养上清液检测结果均为阴性。最后，对马尔尼菲青霉病患者血清的临床评估表明，26例患者中有17例（65%）Mp1p抗原检测呈阳性。此外，还用这些血清标本进行了Mp1p抗体检测。马尔尼菲青霉的抗体和抗原联合检测敏感性为88%（26例中的23例），阳性预测值为100%，阴性预测值为96%。这些检测的特异性很高，因为85份对照血清在两种检测中均无阳性结果。
