Get access

Modulation of a “CD59-like” Protein in Naegleria fowleri Amebae by Bacteria1

Authors

  • ANGELA E. FRITZINGER,

    1. Department of Microbiology and Immunology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, Virginia 23298. USA
    Search for more papers by this author
  • FRANCINE MARCIANO-CABRAL

    Corresponding author
    1. Department of Microbiology and Immunology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, Virginia 23298. USA
    Search for more papers by this author

  • 1

    Symposium presentation “Bacterial Endosymbionts or Pathogens of Free-Living Amebae” presented June 5th during the 56th Annual Meeting of the Society of Protozoologists, June 2–6, 2004, Bryant College, Smithfield, Rhode Island, USA.

Corresponding Author; F. Marciano-Cabral—Telephone number; 804–828–9742; FAX number; 804–828–8220; E-mail; fmcabral@hsc.vcu.edu teria or bacterial toxins. We have determined that the ameba “CD59-like” protein increased in response to co-culture with harmful bacteria.

ABSTRACT

Found in soil and freshwater habitats, Naegleria fowleri are free-living amebae that cause a fatal disease in humans called Primary Amebic Meningoencephalitis. In the natural environment, amebae feed on bacteria. In the infected host, the amebae lyse and ingest nerve tissue. Recently, we have established that N. fowleri expresses a “CD59-like” surface protein, but the function of this protein in the ameba has not been elucidated. In mammalian cells, CD59 is a complement-regulatory protein that inhibits complement-mediated lysis of cells expressing this protein. In the present study, expression of the “CD59-like” protein in response to bacteria and bacterial toxins was investigated by Western immunoblot analysis. Co-culture of N. fowleri with log phase Escherichia coli or Pseu-domonas aeruginosa resulted in differential expression of the “CD59-like” protein. Co-cultures of amebae and bacteria were examined by electron microscopy. The results of our study implicate a possible protective role of the “CD59-like” protein in response to bacterial predators and bacterial toxins, because amebae remained intact after co-culture with bacteria.

Ancillary