The Impact of Lactobacillus casei on the Composition of the Cecal Microbiota and Innate Immune System Is Strain Specific

PLoS One. 2016 May 31;11(5):e0156374. doi: 10.1371/journal.pone.0156374. eCollection 2016.


The probiotic function to impact human health is thought to be related to their ability to alter the composition of the gut microbiota and modulate the human innate immune system. The ability to function as a probiotic is believed to be strain specific. Strains of Lactobacillus casei are commonly utilized as probiotics that when consumed alter the composition of the gut microbiota and modulate the host immune response. L. casei strains are known to differ significantly in gene content. The objective of this study was to investigate seven different L. casei strains for their ability to alter the murine gut microbiota and modulate the murine immune system. C57BL/6 mice were fed L. casei strains at a dose of 108 CFU/day/mouse for seven days and sacrificed 3.5h after the last administration. The cecal content and the ileum tissue were collected for microbiota analysis and immune profiling, respectively. While 5 of the L. casei strains altered the gut microbiota in a strain specific manner, two of the strains did not alter the overall cecal microbiota composition. The observed changes cluster into three groups containing between 1 and 2 strains. Two strains that did not affect the gut microbiota composition cluster together with the control in their impact on pattern recognition receptors (PRRs) expression, suggesting that the ability to alter the cecal microbiota correlates with the ability to alter PRR expression. They also cluster together in their impact on the expression of intestinal antimicrobial peptides (AMPs). This result suggests that a relationship exists between the capability of a L. casei strains to alter the composition of the gut microbiota, PRR regulation, and AMP regulation.

MeSH terms

  • Animals
  • Cecum / microbiology
  • Gastrointestinal Microbiome / genetics
  • Gastrointestinal Microbiome / immunology*
  • Humans
  • Immunity, Innate
  • Lactobacillus casei / classification
  • Lactobacillus casei / immunology*
  • Male
  • Mice, Inbred C57BL
  • Probiotics* / therapeutic use
  • Species Specificity

Grant support

This work was funded by DuPont Inc. (Grant no. PRJ19MQ) and by the WARF (Grant no. PRJ66JZ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.