Clinical and Diagnostic Laboratory Immunology, Jul 1994, 390-393, Vol 1, No. 4
Copyright © 1994 by the American Society for Microbiology. All rights reserved.

Effects of histoplasmin M antigen chemical and enzymatic deglycosylation on cross-reactivity in the enzyme-linked immunoelectrotransfer blot method

RM Zancope-Oliveira, SL Bragg, E Reiss, B Wanke and JM Peralta
Laboratorio de Micologia Medica, Hospital Evandro Chagas, Fundaca Oswaldo Cruz, Rio de Janeiro, Brazil.

The enzyme-linked immunoelectrotransfer blot (EITB) method was evaluated as a suitable method for detecting antibodies against M antigen of Histoplasma capsulatum by use of both glycosylated and deglycosylated M protein of histoplasmin (HMIN). Sera from patients with histoplasmosis, paracoccidioidomycosis, blastomycosis, coccidioidomycosis, and aspergillosis were tested by the EITB with glycosylated M protein of HMIN. This assay demonstrated 100% sensitivity with histoplasmosis serum samples, all of which reacted with the 94-kDa glycoprotein (M antigen). Although the EITB is highly sensitive, it is not specific for histoplasmosis when glycosylated M protein is used as an antigen. A total of 81% of paracoccidioidomycosis, 25% of blastomycosis, 33% of coccidioidomycosis, 73% of aspergillosis, and 16% of tuberculosis serum samples cross-reacted with M protein of HMIN and yielded patterns indistinguishable from those obtained with histoplasmosis serum samples. The EITB reactions with both untreated M antigen and M antigen altered by periodate oxidation or by deglycosylation with endoglycosidases were compared. Cross-reactions with heterologous sera in the EITB could be attributed to periodate-sensitive carbohydrate epitopes, as reflected by the increase in the test specificity from 46.1 to 91.2% after periodate treatment of M protein. The EITB for the detection of antibodies to M antigen is a potential diagnostic test for histoplasmosis, provided that periodate-treated M protein is used as an antigen.

This article has been cited by other articles:

• Guimaraes, A. J., Pizzini, C. V., de Matos Guedes, H. L., Albuquerque, P. C., Peralta, J. M., Hamilton, A. J., Zancope-Oliveira, R. M. (2004). ELISA for early diagnosis of histoplasmosis. J Med Microbiol 53: 509-514 [Abstract] [Full Text]  
• Neves, A. R., Mamoni, R. L., Rossi, C. L., de Camargo, Z. P., Blotta, M. H. S. L. (2003). Negative Immunodiffusion Test Results Obtained with Sera of Paracoccidioidomycosis Patients May Be Related to Low-Avidity Immunoglobulin G2 Antibodies Directed against Carbohydrate Epitopes. CVI 10: 802-807 [Abstract] [Full Text]  
• Yeo, S. F., Wong, B. (2002). Current Status of Nonculture Methods for Diagnosis of Invasive Fungal Infections. Clin. Microbiol. Rev. 15: 465-484 [Abstract] [Full Text]  
• Pizzini, C. V., Zancope-Oliveira, R. M., Reiss, E., Hajjeh, R., Kaufman, L., Peralta, J. M. (1999). Evaluation of a Western Blot Test in an Outbreak of Acute Pulmonary Histoplasmosis. CVI 6: 20-23 [Abstract] [Full Text]