LPS receptor expression and lps binding capacity of monocytes and macrophages in swine]

The expression of the lipopolysaccharide (LPS) receptor CD14, being of importance for an effective immune response, and the direct measurable binding of LPS molecules by alveolar macrophages (AM), peritoneal macrophages (PM) and peripheral blood mononuclear cells (PBMC) of swine were determined. Additionally, the influence of an experimental intrabronchial infection with Pasteurella multocida on these parameters was investigated. Whereas the AM and the PM differed only negligibly regarding their share of CD14 bearing and LPS binding cells, in contrast to AM the intensity of the LPS-binding of PM was significantly higher. Among the PBMC, two populations could be detected which expressed the CD14 with different intensity, whereas the LPS-binding of both populations was similarly pronounced. Following infection of the animals, AM showed an unchanged percentage of CD14 positive cells and simultaneously an increased CD14 receptor expression. On the other hand, the percentage of the LPS-binding cells rose, while no changes of the intensity of LPS-binding were observable. The studies revealed that intrabronchial infection results in local and systemic alterations of CD14 expression and LPS-binding capacity of different cell populations. However, a direct correlation between the appearance of CD14- and LPS-binding does not seem to inevitably exist, indicating probably CD14-independent LPS-binding.