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Updated: Feb 25, 2026

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages
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Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

Published on: October 25, 2017

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COMPLEMENT MEDIATED LYSIS, ADHESION, INVASION, AND MULTIPLICATION WITHIN HeLa CELLS AND HUMAN MONOCYTE MACROPHAGES OF

P Krishna Menon1

  • 1Classified Specialist (Pathology), 7 Air Force Hospital, Nathu Singh Road, Kanpur 208004.

Medical Journal, Armed Forces India
|August 4, 2017
PubMed

Insights

Multiple drug-resistant Salmonella typhi (S. typhi) strains exhibit enhanced resistance to complement killing and increased intracellular multiplication. These factors contribute to the heightened virulence of resistant S. typhi strains.

Area of Science:

  • Microbiology
  • Immunology
  • Infectious Diseases

Background:

  • Salmonella typhi (S. typhi) causes typhoid fever, a significant global health concern.
  • The emergence of multidrug-resistant (MDR) S. typhi strains poses a therapeutic challenge.
  • Understanding the virulence factors of MDR S. typhi is crucial for developing effective treatments.

Purpose of the Study:

  • To compare the susceptibility of susceptible and MDR S. typhi strains to complement lysis.
  • To investigate the cellular invasion and intracellular survival capabilities of susceptible and MDR S. typhi strains.
  • To determine the role of complement resistance and intracellular multiplication in the virulence of MDR S. typhi.

Main Methods:

  • Comparison of complement-mediated killing of susceptible and MDR S. typhi strains.
  • Assessment of S. typhi adherence and invasion of HeLa and human monocyte cell lines.
  • Quantification of intracellular multiplication of S. typhi within human mononuclear macrophages.

Main Results:

  • MDR S. typhi strains demonstrated increased resistance to complement-mediated killing compared to susceptible strains.
  • Antibody enhanced the complement-mediated killing efficiency against both susceptible and MDR S. typhi.
  • Adherence and invasion rates were similar between susceptible and MDR S. typhi strains in cell lines.
  • MDR S. typhi strains exhibited significantly higher intracellular multiplication rates within human mononuclear macrophages after 6 hours.

Conclusions:

  • Decreased susceptibility to complement lysis contributes to the survival of MDR S. typhi.
  • Enhanced intracellular multiplication within macrophages is a key virulence factor for MDR S. typhi.
  • The combination of complement resistance and increased intracellular proliferation likely explains the heightened virulence of MDR S. typhi strains.
Keywords:
ComplementDrug resistanceHeLa cellsHuman monocyte macrophagesPlasmidS. typhi

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