Klebsiella pneumoniae glycoprotein RU-41740 enhances resistance of mice against Mycoplasma arthritidis-induced arthritis

The effect of a purified glycoprotein extract from Klebsiella pneumoniae with non-specific immunostimulating properties (RU 41740) on the development and course of mycoplasma arthritis was investigated. Male A/J mice aged 2-3 months were given RU-41740 either intraperitoneally (i.p.) or orally prior to injection with Mycoplasma arthritidis. RU-41740 injected i.p. at 0.1 mg kg-1 or given orally at 1 mg kg-1 prior to the infection and subsequently on alternate days enhanced the resistance of mice to mycoplasma arthritis (P less than 0.001). Doses of 1 mg kg-1 i.p. or 10 mg kg-1 orally did not modify the course of the arthritis significantly, probably due to immunosuppressive factors from monocytes. It is suggested that RU-41740 protects the mice by stimulating macrophages. This immunostimulant might prove useful in the treatment of mycoplasma diseases, especially in the immunocompromised host.