is a life-threatening and increasingly frequent pathogen of the immunocompromised. Like other filamentous fungi grows in a highly polar manner, adding new cell wall to the apical region of hyphae. mAbs were raised against isolated cell walls. Fifteen antibodies bound reproducibly to isolated cell walls in ELISAs and to the walls of intact cells in immunofluorescence experiments. Surprisingly, individual mAbs showed distinct patterns of localization. Six antibodies labelled exclusively conidial or basal regions, seven labelled apical regions and a single antibody labelled both basal and apical regions of hyphae. Ten antibodies did not label the walls adjacent to septa. In double labelling experiments with representative mAbs there was little or no overlap between epitopes recognized. These labelling patterns suggest that the wall is made up of basal and apical domains that differ in composition or organization and that the wall region flanking septa differs from other regions of the lateral wall. In time-course experiments of early growth, mAb16C4 failed to label isotropically expanding cells and labelled emerging germ tubes and branches. The same mAb failed to label the mutant, which is defective in polarity establishment. However, mAb16C4 did label the mutant, which completes polarity establishment, but is defective in polarity maintenance. Thus, mAb16C4 appears to recognize a cell wall change that occurs during polarity establishment. In immunogold labelling and transmission electron microscopy (TEM) experiments, conidia, basal regions and apical regions of thin-sectioned cells labelled with mAb16C4. That only apical regions labelled in intact cells (immunofluorescence) while conidial, basal and apical regions labelled in thin-sectioned cells (TEM) suggests that the 16C4 epitope is present along the whole hypha, but is masked everywhere except the tip until polarity establishment. That is to say, some remodelling of the wall during polarity establishment exposes the 16C4 epitope. The 16C4 epitope was partially purified from total protein by passage through hydrophobic interaction and anion-exchange columns. The resulting single ELISA-positive fraction showed relatively few bands by SDS-PAGE and silver staining and a strong band by Western blotting with the16C4 mAb. Sequencing of the fraction yielded a predicted peptide with a 6-amino acid exact match to a region of the Cat1 protein previously identified as an immunodominant catalase that localizes to the cell wall and is secreted to the medium. Experiments are under way to determine if mAb16C4 recognizes Cat1 or another protein that co-purifies with Cat1.


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  1. Calera, J. A., Paris, S., Monod, M., Hamilton, A. J., Debeaupuis, J. P., Diaquin, M., Lopez-Medrano, R., Leal, F. & Latge, J. P.(1997). Cloning and disruption of the antigenic catalase gene of Aspergillus fumigatus. Infect Immun 65, 4718–4724. [Google Scholar]
  2. Debeaupuis, J. P., Sarfati, J., Chazalet, V. & Latge, J. P.(1997). Genetic diversity among clinical and environmental isolates of Aspergillus fumigatus. Infect Immun 65, 3080–3085. [Google Scholar]
  3. Denning, D. W.(1998). Invasive aspergillosis. Clin Infect Dis 26, 781–805.[CrossRef] [Google Scholar]
  4. Ellis, M.(1999). Therapy of Aspergillus fumigatus-related diseases. Contrib Microbiol 2, 105–129. [Google Scholar]
  5. Fontaine, T., Mouyna, I., Hartland, R. P., Paris, S. & Latge, J. P.(1997). From the surface to the inner layer of the cell wall. Biochem Soc Trans 25, 194–199. [Google Scholar]
  6. Ghfir, B., Fonvieille, J. L. & Dargent, R.(1997). Influence of essential oil of Hyssopus officinalis on the chemical composition of the walls of Aspergillus fumigatus. Mycopathologia 138, 7–12.[CrossRef] [Google Scholar]
  7. Guest, G. M. & Momany, M.(2000). Analysis of cell wall sugars in the pathogen Aspergillus fumigatus and the saprophyte Aspergillus nidulans. Mycologia 92, 1047–1050.[CrossRef] [Google Scholar]
  8. Harris, S. D.(1997). The duplication cycle in Aspergillus nidulans. Fungal Genet Biol 22, 1–12.[CrossRef] [Google Scholar]
  9. Harris, S. D. & Momany, M.(2004). Polarity in filamentous fungi: moving beyond the yeast paradigm. Fungal Genet Biol 41, 391–400.[CrossRef] [Google Scholar]
  10. Harris, S. D., Morrell, J. L. & Hamer, J. E.(1994). Identification and characterization of Aspergillus nidulans mutants defective in cytokinesis. Genetics 136, 517–532. [Google Scholar]
  11. Hearn, V. M. & Sietsma, J. H.(1994). Chemical and immunological analysis of the Aspergillus fumigatus cell wall. Microbiology 140, 789–795.[CrossRef] [Google Scholar]
  12. Kafer, E.(1977). Meiotic and mitotic recombination in Aspergillus and its chromosomal aberrations. Adv Genetics 19, 33–131. [Google Scholar]
  13. Momany, M.(2002). Polarity in filamentous fungi: establishment, maintenance and new axes. Curr Opin Microbiol 5, 580–585.[CrossRef] [Google Scholar]
  14. Momany, M. & Taylor, I.(2000). Landmarks in the early duplication cycles of Aspergillus fumigatus and Aspergillus nidulans: polarity, germ tube emergence and septation. Microbiology 146, 3279–3284. [Google Scholar]
  15. Momany, M., Westfall, P. J. & Abramowsky, G.(1999).Aspergillus nidulans swo mutants show defects in polarity establishment, maintenance and hyphal morphogenesis. Genetics 151, 557–567. [Google Scholar]
  16. Momany, M., Richardson, E. A. & Van Sickle, C.(2002). Mapping Woronin body position in Aspergillus nidulans. Mycologia 94, 260–266.[CrossRef] [Google Scholar]
  17. Paris, S., Debeaupuis, J. P., Crameri, R., Carey, M., Charles, F., Prevost, M. C., Schmitt, C., Philippe, B. & Latge, J. P.(2003). Conidial hydrophobins of Aspergillus fumigatus. Appl Environ Microbiol 69, 1581–1588.[CrossRef] [Google Scholar]
  18. Pitt, J. I.(1994). The current role of Aspergillus and Penicillium in human and animal health. J Med Vet Mycol 32 (Suppl. 1), 17–32.[CrossRef] [Google Scholar]
  19. Pringle, J. R., Preston, R. A., Adams, A. E. M., Stearns, T., Drubin, D. G., Haarer, B. K. & Jones, E. W.(1989). Fluorescence microscopy methods for yeast. Methods Cell Biol 31, 357–435. [Google Scholar]
  20. Sietsma, J. H. & Wessels, J. G. H.(1994). Apical wall biogenesis. In The Mycota, pp. 126–141. Edited by J. G. H. Wessels & F. Meinhardt. Berlin: Springer.
  21. Ste-Marie, I., Senechal, S., Boushira, M., Garzon, S., Strykowski, H., Pedneault, L. & de Repentigny, L.(1990). Production and characterization of monoclonal antibodies to cell wall antigens of Aspergillus fumigatus. Infect Immun 58, 2105–2114. [Google Scholar]

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