Stimulation of human PMNs in vitro by a succinimide molecular complex of methylfurylbutyrolactone

The immunopotentiating effects on human neutrophils of a new synthetic immune biological response modifer were studied. The compound is a succinimide crystalline molecular complex of methylfurylbutyrolactone (MFBL). The MFBL succinimide (MFBL-S) derivative was tested for its in vitro effects on polymorphonuclear leukocyte (PMN) functions. At microgram quantities, MFBL-S stimulated a twofold increase in: directed migration of PMNs; adherence to nylon; and uptake of E. coli lipopolysaccharide. The MFBL-S enhanced phagocytosis by PMNs of S. epidermidis and E. coli. Additionally, intracellular killing of S. epidermidis by MFBL-S treated PMNs was significantly increased at all doses studied, whereas killing of E. coli was only significantly different from controls at concentrations of 10 micrograms/ml.