Effects of Pretreatment with PSK, a Protein-Bound Polysaccharide, on Escherichia Coli Infection in Mice

Abstract

Only 17% of mice inoculated with lethal doses of Escherichia coli survived for 5 days after the challenge. Significant antibacterial activity of PSK, a protein-bound polysaccharide, was induced when the mice were pretreated with 40 mg/kg of PSK by an intraperitoneal, subcutaneous or intramuscular route, but not by an intravenous route, 48 hr before the E. coli inoculation. Repeated oral administration of PSK for 2 weeks (20 mg/kg, 3 times per week) before E. coli inoculation was also effective. Intraperitoneal administration of PSK was most potent, inducing significant polymorphonuclear cell accumulation and generation of luminol-dependent chemiluminescence by peritoneal exudate cells, with a peak 24 hr after administration of the PSK.