Differential sensitivity of peripheral blood granulocytes, monocytes, and lymphocytes to endotoxin-induced apoptosis in patients who have sustained Salmonella infection

The differential sensitivity of peripheral blood granulocytes, monocytes, and lymphocytes to endotoxin-induced apoptosis was studied in convalescents with Salmonella infection. The number of early (Tunel+PI-) and late (Tunel+PI+) apoptotic cells and the rate of apoptosis (the relative content of DNA apoptotic fragments in the solitary cell) were determined on a FACSCalibur cytofluorometer, by applying a package of the CellQuest programs (Becton Dickinson). A higher threshold of sensitivity of granulocytes, monocytes, and lymphocytes to the apoptotic effect of low, suboptimal doses (100 ng), as well as suppression of early stages of apoptosis by the optimal doses (1000 ng) of S. enteritidis lypopolysaccharides (LPS) were observed in patients who had sustained salmonellosis at a stage of reconvalescence. The hierarchy of LPS-induced apoptosis (granulocyte--monocyte--lymphocyte), observed in healthy donors, was also retained in the group of patients receiving the suboptimal doses of LPS, which seems to be associated with the repeated action of toxin on sensitized cell populations.