Differences in phagocytosis by polymorphonuclear leucocytes (PMNs) and monocytes (Mos) in endotoxemia and endotoxin (ET) tolerance

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Flow cytometry offers a rapid method to quantitate phagocytosis by PMNS and Mos. Since the PMN is a major defense beside the Mos against bacterial infection we compared both systems in a porcine endotoxin shock model in control animals (C) and endotoxin-tolerant animals (T). A commercial test kit (phagotest, Orpegen, Heidelberg, Germany) was used for demonstrating ingestion of opsonized fluorescent E. coli (FI) and phagocytosing cells (PC). Seven pigs were pretreated over five days with increasing doses of atoxic endotoxin from Rhodopseudomonas sphaeroides (T) before induction of an ET shock with ET from Salmonella friedenau at a dose of 250 ng/kg BW/h, like the controls who were not pre-treated.

Results of both groups were expressed in fluorescence intensity (FI) and summarized in the Table.

The functional assessment of Mos and PMNS in our shock model revealed an enhancement of phagocytic activity in endotoxin-tolerant animals both in Mos and PMNS with the highest increase in the latter.

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