TLR2/6 stimulation of the rat lung: effects on lymphocyte subsets, natural killer cells and dendritic cells in different parts of the air-conducting compartments and at different ages

Immunology. 2009 Jan;126(1):132-9. doi: 10.1111/j.1365-2567.2008.02886.x. Epub 2008 Jun 19.


The composition of lymphocyte subsets in the lung has been found to be compartment-specific. To characterize the effect of age, weanling, young adult and adult rats were studied in control conditions and after a single intratracheal dose of the Toll-like receptor 2/6 (TLR2/6) agonist macrophage activating lipopeptide-2 (MALP-2). In all age groups, T, B and natural killer (NK) cells increased dramatically in the epithelium and lamina propria of the bronchi. Male adult rats were found to have responded to MALP-2 to a much greater extent than females when lymphocyte subsets were counted in the epithelium and the lamina propria. In a second series of experiments the time kinetics of regulatory T-cell (Treg) subsets and dendritic cells (DCs) in the lung was studied after local stimulation with MALP-2. Different time-dependent patterns were found in the Treg subsets CD4(+) CD25(+), CD4(+) CD25(+) neuropilin 1(+) and CD4(+) CD25(+) Foxp3(+) cells. Neutrophils and DCs also showed different patterns. Thus, the local application of a TLR agonist increased the number of lymphocyte subsets in a compartment-specific pattern. However, data should not be generalized or extrapolated from one age group, sex or lymphocyte subpopulation to another.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / immunology
  • Animals
  • Bronchi / immunology
  • Dendritic Cells / immunology
  • Epithelial Cells / immunology
  • Female
  • Killer Cells, Natural / immunology*
  • Lipopeptides / immunology
  • Lung / immunology*
  • Lymphocyte Subsets / immunology*
  • Male
  • Rats
  • Rats, Inbred Lew
  • Respiratory Mucosa / immunology
  • Toll-Like Receptor 2 / agonists
  • Toll-Like Receptor 2 / immunology*
  • Toll-Like Receptor 6 / agonists
  • Toll-Like Receptor 6 / immunology*


  • Lipopeptides
  • Tlr2 protein, rat
  • Toll-Like Receptor 2
  • Toll-Like Receptor 6
  • macrophage stimulatory lipopeptide 2