Lung IkB and NFkB with neutrophilia in vivo in a gram positive infection model

Gram‐positive infections have increased over the past few years; unfortunately, our mechanistic knowledge of the related inflammatory processes remains incomplete. Transcription factor NFkB coordinates activation of many genes involved in host defense, and the IkB‐NFkB cascade strongly recruits PMN in gram negative studies. To investigate the involvement of NFkB in a gram positive model, abdominal tissue cage infections were produced by a patient strain of TSST‐producing S. aureus . Lungs were evaluated by histostain and laser scanning confocal microscopy to quantify IkB and NFkB. Their presence was compared to clinical infection markers. Following harvest at 1 week, lung sections were stained with anti‐ IkB or NFkB (Santa Cruz) followed by appropriate secondary antibodies tagged with FITC or Texas Red, and evaluated by confocal microscopy. Tissues/ fluids for clinical infection markers were collected at necropsy. Tissue TNF alpha averaged 300 pg/mL infected vs.74 in controls. Tissue cage fluid showed a single S. aureus strain, 10 9 /mL. Lung H&E indicated granulocytic inflammatory infiltrate. Lung sections, seen by confocal microscopy double staining, showed that NFkB, normally bound to IkB in the cytoplasm, was released in bronchial epithelial cells, (34.2 stain intensity vs. 0 control). IkB was seen at high levels in the sub epithelial layer (36.1 intensity). The prominent PMN influx to lung seen with the distant gram positive infection may relate to IkB in the airway, as reported by the work of others. Our data demonstrated in vivo the processes suggested by lung cell culture, and provide a catalyst to investigations of these factors in the pathophysiology of inflammation. Funding: UMKC Med. internal