An investigation of the role of soluble CD14 in hospitalized, sick horses

The objectives of this study were to (1) evaluate the effects of equine soluble CD14 (sCD14) and monoclonal antibodies (mAb) to equine CD14 on lipopolysaccharide-induced tumor necrosis factor α (TNF-α) secretion from equine peripheral blood mononuclear cells (PBMC); and to (2) determine serum concentrations of sCD14 in a population of horses with gastrointestinal diseases or other illnesses likely to result in endotoxemia. Equine PBMC isolated from 10 healthy horses were incubated with Escherichia coli LPS plus CD14 mAb or sCD14 and assayed for TNF-α activity. Pre-incubation with CD14 mAb did not inhibit LPS-induced TNF-α production, whereas use of sCD14 inhibited LPS-induced TNF-α production in a concentration-dependent manner. Additionally, blood samples from 55 ill and 23 healthy horses were used to determine serum concentrations of sCD14. Concentrations of sCD14 were positively correlated to respiratory rate, duration of clinical signs and band neutrophil count. Although serum sCD14 was significantly increased in the ill horses compared to healthy horses, sCD14 did not correlate with outcome. Results of this study indicate that release of sCD14 is increased in ill horses and that TNF-α production by PBMC is decreased when cells are treated with sCD14.