Related Experiment Video
Updated: Apr 22, 2026
Isolation and Th17 Differentiation of Naïve CD4 T Lymphocytes
Published on: September 26, 2013
Interleukin 17 regulates Mer tyrosine kinase-positive cells in Pseudomonas aeruginosa keratitis
Cui Li1, Sharon A McClellan2, Ronald Barrett2
1Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, China.
Purpose:
To determine if IL-17 regulates Mer tyrosine kinase-positive (MerTK+) cells in Pseudomonas aeruginosa keratitis.
Methods:
Interleukin 17 was tested in normal and infected cornea of susceptible C57BL/6 and resistant BALB/c mice. The latter were treated with recombinant mouse (rm) IL-17; both groups were treated with IL-17 neutralizing antibody. Mice were infected, and clinical score, PCR, ELISA, and myeloperoxidase (MPO) assays tested expression of proinflammatory and anti-inflammatory mediators and polymorphonuclear neutrophilic leukocyte (PMN) infiltrate. Fas and Fas ligand (FasL) protein levels were assessed in both mouse strains, while MerTK+ cells were examined by immunostaining and cell sorting before and after IL-17 neutralization.
Results:
The IL-17 mRNA and protein were higher in C57BL/6 versus BALB/c cornea after infection. The rmIL-17 treatment of BALB/c mice modified proinflammatory and anti-inflammatory mediators, but clinical score and MPO assay revealed no differences. However, only BALB/c mice treated with IL-17 neutralizing antibody showed increased disease, macrophage inflammatory protein (MIP) 2, and MPO levels. Fas and FasL protein levels, elevated earlier in BALB/c versus C57BL/6 mice, correlated with significantly more MerTK+ cells in BALB/c cornea at 3 days after infection. Neutralization of IL-17 in C57BL/6 mice elevated MerTK+ cells, while similar treatment of BALB/c mice significantly decreased them.
Conclusions:
These data provide evidence that IL-17 expression is higher in C57BL/6 versus BALB/c cornea after infection and that the latter group has more MerTK+ cells. Exogenous rmIL-17 failed to shift the disease response in resistant mice, but its neutralization resulted in worsened disease and reduced MerTK+ cells. Neutralization of IL-17 in C57BL/6 mice increased MerTK+ cells but did not dramatically shift the disease response.
Insights
Interleukin 17 (IL-17) levels influence Mer tyrosine kinase-positive (MerTK+) cells during Pseudomonas aeruginosa keratitis. Neutralizing IL-17 worsened disease in resistant mice but increased MerTK+ cells in susceptible mice.
Area of Science:
- Ophthalmology
- Immunology
- Microbiology
Background:
- Pseudomonas aeruginosa keratitis is a severe eye infection.
- Interleukin 17 (IL-17) is a key cytokine in host defense and inflammation.
- Mer tyrosine kinase (MerTK) plays a role in immune cell regulation.
Purpose of the Study:
- To investigate the role of IL-17 in regulating MerTK-positive (MerTK+) cells during P. aeruginosa keratitis.
- To compare IL-17 effects in susceptible (C57BL/6) and resistant (BALB/c) mouse models.
Main Methods:
- Mice were infected with P. aeruginosa, and IL-17 levels were measured.
- Recombinant IL-17 and IL-17 neutralizing antibodies were administered.
- Clinical scores, inflammatory mediators (PCR, ELISA), and immune cell infiltration (MPO) were assessed.
- MerTK+ cells were quantified using immunostaining and cell sorting.
Main Results:
- IL-17 expression was higher in susceptible mice post-infection.
- IL-17 neutralization exacerbated disease and increased myeloid cells in resistant mice.
- IL-17 neutralization increased MerTK+ cells in susceptible mice but decreased them in resistant mice.
Conclusions:
- IL-17 plays a differential role in regulating MerTK+ cells and disease severity in P. aeruginosa keratitis.
- Modulating IL-17 offers potential therapeutic strategies for bacterial keratitis.
