Lung Inflammation Induced by Lipoteichoic Acid or Lipopolysaccharide in Humans

Rationale: Recognition of pathogen-associated molecular patterns by Toll-like receptors (TLRs) is considered to be important for an appropriate immune response against pathogens that enter the lower airways.Objectives: We studied the effects of two different TLR agonists relevant for respiratory infections in the human lung: lipoteichoic acid (LTA; TLR2 agonist, component of gram-positive bacteria) and lipopolysaccharide (LPS; TLR4-agonist, component of gram-negative bacteria).Methods: Fifteen healthy subjects were given LPS or LTA: by bronchoscope, sterile saline was instilled into a lung segment followed by instillation of LTA or LPS into the contralateral lung. After 6 hours, a bronchoalveolar lavage was performed and inflammatory parameters were determined. Isolated RNA from purified alveolar macrophages was analyzed by multiplex ligation–dependent probe amplification. In addition, spontaneous cytokine release by alveolar macrophages was measured.Measurements and Main Results: Marked differences were ...