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Neisserial Opa Protein-CEACAM Interactions: Competition for Receptors as a Means of Bacterial Invasion and

Jennifer N Martin1, Louise M Ball1, Tsega L Solomon1

  • 1Department of Chemistry and ‡Department of Microbiology, Immunology, and Cancer Biology, University of Virginia , Charlottesville, Virginia 22903, United States.

Biochemistry
|July 22, 2016
PubMed

Insights

Pathogenic bacteria use Opa proteins to interact with CEACAMs, triggering cell engulfment. Recombinant Opa proteins bind CEACAMs but lack native specificity, offering insights into bacterial invasion and therapeutic delivery.

Area of Science:

  • Microbiology
  • Cell Biology
  • Immunology

Background:

  • Carcino-embryonic antigen-like cellular adhesion molecules (CEACAMs) mediate cell-cell interactions and signaling.
  • Pathogenic Neisseria bacteria utilize Opa proteins to engage CEACAMs, inducing host cell phagocytosis.
  • Understanding this interaction is crucial for Neisserial pathogenesis and host cell manipulation.

Purpose of the Study:

  • To investigate the in vitro interaction of recombinant Opa proteins with CEACAMs.
  • To compare the receptor specificity of recombinant Opa proteins with native Opa proteins.
  • To explore the implications of CEACAM-mediated engulfment for therapeutic applications.

Main Methods:

  • Reconstitution of Opa proteins into liposomes.
  • In vitro binding assays with CEACAMs.
  • Affinity measurements using techniques like surface plasmon resonance (SPR).

Main Results:

  • Recombinant Opa proteins recognize and bind CEACAMs in vitro.
  • Receptor specificity is not fully maintained in recombinant Opa proteins compared to native forms.
  • Two Opa proteins exhibit nanomolar affinity for CEACAMs, suggesting a mechanism to overcome host cell interactions.

Conclusions:

  • High-affinity Opa protein-CEACAM interactions are essential for Neisserial invasion.
  • CEACAMs can be exploited by pathogens to induce phagocytosis in non-professional phagocytic cells.
  • These findings have potential applications in targeted drug delivery and imaging agent development.

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