Related Experiment Videos
Multiplication of Listeria monocytogenes in a murine hepatocyte cell line
S Wood1, N Maroushek, C J Czuprynski
1Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison 53706.
Abstract:
Listeria monocytogenes was shown to invade and multiply in a murine hepatocyte cell line (ATCC TIB73). Hemolytic and nonhemolytic L. monocytogenes strains exhibited similar abilities to invade hepatocytes, but only hemolytic L. monocytogenes multiplied within this cell line. Microscopic evaluation of monolayers stained with Wright stain demonstrated focal necrosis (plaques) in the hepatocyte monolayers, with large numbers of intracellular listeriae visible within the hepatocytes that lined the margins of these plaques. Murine recombinant interleukin-1 alpha, human recombinant tumor necrosis factor alpha, and murine recombinant gamma interferon did not affect the multiplication of L. monocytogenes in the hepatocytes. These data confirm in vivo observations of the intracellular multiplication of L. monocytogenes in hepatic lesions in infected mice.
Insights
Hemolytic Listeria monocytogenes strains invade and multiply in mouse liver cells, causing cell death. Nonhemolytic strains only invade, highlighting the role of hemolysis in Listeria pathogenesis.
Area of Science:
- Microbiology
- Cell Biology
- Immunology
Background:
- Listeria monocytogenes is a foodborne pathogen that can cause severe infections.
- The pathogen is known to invade host cells, but the mechanisms of intracellular multiplication and host cell damage are not fully understood.
Purpose of the Study:
- To investigate the invasion and intracellular multiplication of Listeria monocytogenes in a murine hepatocyte cell line.
- To determine the role of hemolytic activity in Listeria monocytogenes pathogenesis within hepatocytes.
Main Methods:
- Invasion and multiplication assays using a murine hepatocyte cell line (ATCC TIB73).
- Microscopic evaluation of infected hepatocyte monolayers.
- Assessment of cytokine effects (interleukin-1 alpha, tumor necrosis factor alpha, gamma interferon) on bacterial multiplication.
Main Results:
- Both hemolytic and nonhemolytic Listeria monocytogenes strains invaded hepatocytes similarly.
- Only hemolytic strains multiplied within the hepatocytes.
- Intracellular Listeria monocytogenes were observed within hepatocytes lining necrotic lesions (plaques).
- Cytokines did not influence bacterial multiplication in hepatocytes.
Conclusions:
- Hemolytic activity is crucial for Listeria monocytogenes multiplication within hepatocytes.
- Intracellular Listeria monocytogenes contribute to hepatocyte necrosis.
- These findings in vitro support in vivo observations of hepatic lesions in Listeria-infected mice.