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Uptake of pp65 in in vitro generated pp65-positive polymorphonuclear cells mediated by phagocytosis and cell fusion?

A M Kas-Deelen1, T H The, N Blom

  • 1Department of Clinical Immunology, University Hospital Groningen, Groningen, The Netherlands.

Intervirology
|February 27, 2001
PubMed
Abstract

Insights

Cytomegalovirus (CMV) antigenemia involves polymorphonuclear granulocytes (PMN) internalizing viral pp65 protein. This study reveals that both viral particle fusion and phagocytosis contribute to pp65 uptake by PMN.

Area of Science:

  • Virology
  • Immunology
  • Cell Biology

Background:

  • Cytomegalovirus (CMV) antigenemia is diagnosed by detecting CMV pp65 protein within polymorphonuclear granulocytes (PMN).
  • The precise mechanisms by which PMN acquire viral particles or proteins leading to antigenemia remain incompletely understood.

Purpose of the Study:

  • To investigate the in vitro mechanisms of pp65 uptake by PMN.
  • To elucidate how pp65 gains nuclear expression within PMN in an experimental model of CMV antigenemia.

Main Methods:

  • Utilized an in vitro model involving coculture of PMN with CMV-infected endothelial cells.
  • Employed a series of inhibitors targeting different cellular uptake mechanisms.
  • Conducted morphological analyses using light and transmission electron microscopy.

Main Results:

  • Inhibitors of cellular actin (cytochalasin B) and microtubule (nocodazole) polymerization significantly reduced pp65 uptake by PMN.
  • Anti-CMV hyperimmune globulin and lactoferrin decreased the number of pp65-positive PMN.
  • Morphological analysis revealed viral particles within PMN cytoplasm and evidence of PMN fusion into larger multinucleated cells.

Conclusions:

  • Both phagocytosis and fusion of viral particles with PMN are critical mechanisms for pp65 uptake.
  • These findings provide insight into the cellular processes underlying CMV antigenemia.

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