IN-VIVO STUDY ON THE IMMUNOMODULATING EFFECTS OF OM-85 BV ON SURVIVAL, INFLAMMATORY CELL RECRUITMENT AND BACTERIAL CLEARANCE IN KLEBSIELLA-PNEUMONIA

Oral administration of the bacterial extract OM-85 BV has been shown t o prime alveolar macrophages (AM) in such a way that they secrete sign ificantly more nitric oxide, tumor necrosis factor-alpha and interleuk in-1 beta upon in vitro stimulation with lipopolysaccharide (LPS). As increased cytokine secretion by AM may account for the therapeutic eff ect of OM-85 BV in respiratory tract infections, we studied the effect of orally administered OM-85 BV on the outcome of Klebsiella pneumoni ae-induced pneumonia. Mice received a daily oral dose of OM-85 BV (350 mg/kg body weight) for 5 days and were intratracheally infected with 333, 1000 or 3333 CFU K. pneumoniae on day 8. It was shown that OM-85 BV pretreatment of mice has no effect on bacterial clearance, neutroph il recruitment and survival in this acute respiratory tract infection. Also, OM-85 BV treatment had no protective effect in a recurrent infe ction with K. pneumoniae. It is concluded that AM activation by oral t reatment with OM-85 BV is not sufficient to play a protective role in respiratory tract infection with K. pneumoniae. (C) 1998 Published by Elsevier Science Ltd on behalf of the International Society for Immuno pharmacology.