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Streptococcus pneumoniae induces mast cell degranulation

Giovanna Barbuti1, Monica Moschioni, Stefano Censini

  • 1Dipartimento di Scienze Biomediche e Oncologia Umana, Sezione di Patologia Generale, Università di Bari, P.zza Giulio Cesare 11, I-70124 Bari, Italy.

International Journal of Medical Microbiology : IJMM
|March 15, 2006
PubMed

Insights

Streptococcus pneumoniae triggers mast cell degranulation, a key innate immune response. This interaction may help the bacteria spread from the respiratory tract without causing inflammation.

Area of Science:

  • Immunology
  • Microbiology
  • Bacterial Pathogenesis

Background:

  • Streptococcus pneumoniae is a common nasopharyngeal colonizer.
  • Pneumococci can cause severe invasive diseases.
  • Mast cells are crucial innate immune cells in respiratory mucosa.

Purpose of the Study:

  • To investigate the interaction between S. pneumoniae and mast cells.
  • To understand the mechanism of mast cell activation by pneumococci.
  • To explore the role of this interaction in bacterial dissemination.

Main Methods:

  • Co-culture of various S. pneumoniae strains with the RBL-2H3 mast cell line.
  • Assessment of mast cell degranulation.
  • Measurement of cytosolic calcium levels.
  • Quantification of TNF-alpha and IL-6 production.

Main Results:

  • Live S. pneumoniae induced dose- and time-dependent mast cell degranulation.
  • Degranulation was partially dependent on cytosolic calcium.
  • No significant production of TNF-alpha or IL-6 was observed.
  • Non-encapsulated strains showed varying degranulation potentials.

Conclusions:

  • S. pneumoniae can induce mast cell degranulation without triggering a major pro-inflammatory cytokine response.
  • This mechanism may facilitate bacterial spread from the respiratory mucosa.
  • Bacterial factors likely mediate degranulation, representing a potential adaptation for host colonization and dissemination.

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