Adherence of Brucella to human epithelial cells and macrophages is mediated by sialic acid residues

Cell Microbiol. 2004 May;6(5):435-45. doi: 10.1111/j.1462-5822.2004.00372.x.


The basis for the interaction of Brucella species with the surface of epithelial cells before migration in the host within polymorphonuclear leucocytes is largely unknown. Here, we studied the ability of Brucella abortus and Brucella melitensis to adhere to cultured epithelial (HeLa and HEp-2) cells and THP-1-derived macrophages, and to bind extracellular matrix proteins (ECM). The brucellae adhered to epithelial cells forming localized bacterial microcolonies on the cell surface, and this process was inhibited significantly by pretreatment of epithelial cells with neuraminidase and sodium periodate and by preincubation of the bacteria with heparan sulphate and N-acetylneuraminic acid. Trypsinization of epithelial cells yielded increased adherence, suggesting unmasking of target sites on host cells. Notably, the brucellae also adhered to cultured THP-1 cells, and this event was greatly reduced upon removal of sialic acid residues from these cells with neuraminidase. B. abortus bound in a dose-dependent manner to immobilized fibronectin and vitronectin and, to a lesser extent, to chondroitin sulphate, collagen and laminin. In sum, our data strongly suggest that the adherence mechanism of brucellae to epithelial cells and macrophages is mediated by cellular receptors containing sialic acid and sulphated residues. The recognition of ECM (fibronectin and vitronectin) by the brucellae may represent a mechanism for spread within the host tissues. These are novel findings that offer new insights into understanding the interplay between Brucella and host cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Adhesion / physiology*
  • Brucella abortus / physiology*
  • Brucella abortus / ultrastructure
  • Brucella melitensis / metabolism*
  • Brucella melitensis / ultrastructure
  • Cell Line
  • Enzyme Inhibitors / metabolism
  • Epithelial Cells / metabolism
  • Epithelial Cells / microbiology*
  • Epithelial Cells / ultrastructure
  • Extracellular Matrix Proteins / chemistry
  • Extracellular Matrix Proteins / metabolism
  • Humans
  • Macrophages / cytology
  • Macrophages / metabolism*
  • Macrophages / microbiology
  • N-Acetylneuraminic Acid / metabolism*
  • Neuraminidase / metabolism
  • Periodic Acid / metabolism
  • Trypsin / metabolism


  • Enzyme Inhibitors
  • Extracellular Matrix Proteins
  • Periodic Acid
  • metaperiodate
  • Neuraminidase
  • Trypsin
  • N-Acetylneuraminic Acid